Allied Command Operations (ACO)

  • Last updated: 27 May. 2024 16:27

Allied Command Operations (ACO) is responsible for the planning and execution of all Alliance operations. It consists of a small number of permanently established headquarters, each with a specific role. Supreme Allied Commander Europe – or SACEUR – assumes the overall command of operations at the strategic level and exercises his responsibilities from the headquarters in Mons, Belgium: Supreme Headquarters Allied Powers Europe, more commonly known as SHAPE.

Allied Command Operations headquarters


  • ACO, with its headquarters at SHAPE near Mons, Belgium is responsible for the planning and execution of all NATO military operations and is headed by SACEUR.
  • It has the ability to operate at three overlapping levels: strategic, operational and tactical.
  • The command’s overall aim is to contribute to Allied defence and security by maintaining the integrity of Alliance territory, safeguarding freedom of the seas and economic lifelines, and to preserve or restore the security of its members.
  • Allied Command Operations is one of two Strategic Commands at the head of NATO’s military command structure. The other is Allied Command Transformation, which is responsible for ensuring NATO’s military structure and capabilities remain relevant, capable and credible in a rapidly changing world.
  • ACO consists of a number of permanently established headquarters operating at the strategic, operational and tactical levels; they are augmented by national forces assigned to NATO for specific standing and/or crisis roles and tasks.


The structure of Allied Command Operations

ACO is one of two Strategic Commands within NATO's military command structure; the other is Allied Command Transformation (ACT), which – as its name indicates – leads the transformation of NATO's military structure, forces, capabilities and doctrine. Together with their subordinate organisations, they form what is called the NATO Command Structure (NCS), whose function is first and foremost to be able to respond to security threats to the Alliance and, should deterrence fail, provide a capable and effective military response to an armed attack against the territory of any of the NATO Allies.

Ultimately, the NCS plays an essential role in preserving cohesion and solidarity within the Alliance. It, maintains and strengthens the vital link, between Europe and North America, and promotes the principle of equitable sharing among Allies of the roles, risks and responsibilities, as well as the benefits of collective defence.

ACO is a three-tier command with headquarters and supporting elements at the strategic, operational and tactical levels. It exercises command and control of static and deployable headquarters, as well as joint and combined forces across the full range of the Alliance's military operations, missions, operations and tasks. Joint forces are forces from two or more military services (for instance, land, maritime or air) working under a single command; combined forces are forces from different countries working under a single command.

SHAPE, at the strategic level, is at the head of nine operational commands.

At the 2018 Brussels Summit, Allies agreed to strengthen the military backbone of the Alliance. They decided to establish a Cyberspace Operations Centre in Belgium to provide situational awareness and coordination of NATO operational activity within cyberspace; a Joint Force Command Norfolk headquarters in the United States to focus on protecting the transatlantic lines of communication; and a Joint Support and Enabling Command in Ulm, Germany, to ensure freedom of operation and sustainment in the rear area in support of the rapid movement of troops and equipment into, across and from Europe. These new entities are all operational and have reached varying degrees of capability development. Moreover, in October 2020, Allies agreed to establish a NATO Space Centre in Ramstein, Germany; it will help to increase the Alliance’s awareness of challenges in space and its ability to deal with them.

Strategic-level command: SHAPE

SHAPE is a strategic headquarters. Its role is to prepare, plan, conduct and execute NATO military operations, missions and tasks in order to achieve the strategic objectives of the Alliance. As such, it contributes to the deterrence of aggression and the preservation of peace, security and the territorial integrity of Alliance.

ACO is headed by SACEUR, who exercises his responsibilities from SHAPE. Traditionally, he is a United States Flag or General officer. SACEUR is dual-hatted as he is also the commander of the US European Command, which shares many of the same geographical responsibilities as ACO. SACEUR is responsible to the Military Committee (MC), which is the senior military authority in NATO under the overall political authority of the North Atlantic Council (NAC) and the Nuclear Planning Group (NPG). The MC is the primary source of military advice to the NAC and NPG.

Operational-level commands: Brunssum, Naples and Norfolk

The operational level consists of three standing Joint Force Commands (JFCs): one in Brunssum, the Netherlands, one in Naples, Italy and one in Norfolk, Virginia, USA. All stand ready to plan, conduct and sustain NATO operations of different size and scope. Effectively, they need to be able to manage a major joint operation either from their static location, or from a deployed headquarters when operating directly in a theatre of operation. In the latter case, the deployed headquarter is referred to as a Joint Task Force HQ or JTFHQ and should be able to operate for a period of up to one year.

When deployed, a Joint Force Command is only charged to command one operation at a time. However, the elements of the Joint Force Command which have not deployed can provide support to other operations and missions. When a Joint Force Command is not deployed, it can assist ACO in dealing with other headquarters which are deployed in theatre for day-to-day matters and assist, for instance, with the training and preparation for future rotations.

The three commands at this level are also responsible for engaging with key partners and regional organisations in order to support regional NATO HQ tasks and responsibilities, as directed by SACEUR. Additionally, they support the reinforcement of cooperation with partners participating in NATO operations and help to prepare partner countries, which so wish, for NATO membership.

Tactical-level commands: Izmir (Land), Northwood (Maritime) and Ramstein (Air)

The tactical (or component) level consists of what are called Single Service Commands (SSCs): land, maritime and air commands. These service-specific commands provide expertise and support to the Joint Force Commands. They report directly to SHAPE and come under the command of SACEUR.

  • Land Command, Headquarters Allied Land Command (HQ LANDCOM), Izmir, Türkiye: this command's role is to provide a deployable land command and control capability in support of a Joint Force Command running an operation larger than a major joint operation. It can also provide the core land capability for a joint operation (major or not) or a deployable command and control capability for a land operation. Izmir is also the principal land advisor for the Alliance and contributes to development and transformation, engagement and outreach within its area of expertise.
  • Maritime Command, Headquarters Allied Maritime Command (HQ MARCOM), Northwood, the United Kingdom: this command's role is to provide command and control for the full spectrum of joint maritime operations and tasks. From its location in Northwood, it plans, conducts and supports joint maritime operations. It is also the Alliance's principal maritime advisor and contributes to development and transformation, engagement and outreach within its area of expertise. Northwood is able to command a small maritime joint operation or act as the maritime component in support of an operation larger than a major joint operation.
  • Air Command, Headquarters Allied Air Command (HQ AIRCOM), Ramstein, Germany: this command's role is to plan and direct the air component of Alliance operations and missions, and the execution of Alliance air and missile defence operations and missions. Ramstein is also the Alliance's principal air advisor and contributes to development and transformation, engagement and outreach within its area of expertise. Ramstein, with adequate support from within and outside the NATO Command Structure can provide command and control for a small joint air operation from its static location, i.e., from Ramstein or can act as Air Component Command to support an operation which is as big or bigger than a major joint operation. To reinforce its capability, Ramstein has additional air command and control elements available: two Combined Air Operations Centres (CAOC) and a Deployable Air Command and Control Centre (DACCC). The air elements are also structured in a more flexible way to take account of the experience gained in NATO-led operations.

Tactical Air Command and Control

To carry out its missions and tasks, HQ AIRCOM (Ramstein) is supported by Combined Air Operations Centres (CAOC) in Torrejon, Spain and in Uedem, Germany, as well as one Deployable Air Command and Control Centre (DACCC) in Poggio Renatico, Italy.

  • CAOCs: both the CAOC in Spain and in Germany are composed of two parts. One part is a Static Air Defence Centre (SADC) responsible for air policing and the other, a Deployable Air Operations Centre (D-AOC), which supports operations. The D-AOC is an element focused on the production of combat plans and the conduct of combat operations. It has no territorial responsibilities assigned during peacetime, but supplements HQ AIRCOM when required.
  • DACCC: this entity based in Italy consists of three elements. Firstly, a Deployable Air Control Centre + Recognized Air Picture Production Centre + Sensor Fusion Post (DARS). The DARS is responsible for the control of air missions including surface-to-air missiles, air traffic management and control, area air surveillance and production of a recognised air picture and other tactical control functions; secondly, a D-AOC, which has the same role as a CAOC; and thirdly, a Deployable Sensors Section, which provides both air defence radar and passive electronic support measures tracker capabilities that are deployable.

Communication and information systems

Communication and information systems (CIS) consists of two entities: deployable CIS capabilities and static CIS capabilities.

The NATO CIS Group (NCISG) based in Mons, Belgium provides deployable communications and information systems support for ACO. The NATO CIS Group is responsible for provision of all deployable CIS capabilities, as well as CIS operations and exercises planning and control. It acts as the coordinating authority for command and control services support to operations. Provision of the static and central CIS capabilities is the responsibility of the NATO Communications and Information Agency (NCIA), which is not part of the NATO Command Structure.

The NATO CIS Group is supported by three NATO Signals Battalions located at Wesel, Germany, Grazzanise, Italy, and Bydgoszcz, Poland. These three are complemented by various smaller elements (Deployable CIS modules) elsewhere.


Associated assets: STRIKFORNATO, AWACS and AGS

Naval Striking and Support Forces NATO (STRIKFORNATO), NATO Airborne Early Warning and Control Force (NAEW&CF) and Alliance Ground Surveillance (AGS) are part of the NATO Immediate Response Capability. These are multinational structures initially established and made available to the Alliance by memoranda of understanding and technical agreements signed by the respective contributing countries, and are now part of the NATO Command Structure.

STRIKFORNATO is a rapidly deployable maritime headquarters that provides scalable command and control across the full spectrum of the Alliance’s fundamental security tasks. It focuses on maritime operations and, as part of NATO reforms, has moved from Italy to Portugal. It comprises 13 participating countries and serves as a link for integrating US maritime forces into NATO operations.

The NAEW&C Force comprises three elements: a multinational HQ (Geilenkirchen) and two operational components, the multinational E-3A and the E-3D. NATO Air Base (NAB) Geilenkirchen, Germany, is home to 14 Boeing E-3A 'Sentry' AWACS aircraft. NATO operates this fleet, which provides the Alliance with an immediately available airborne command and control (C2), air and maritime surveillance and battle-space management capability. The fleet of six Boeing E-3D aircraft based in Waddington, Lincolnshire, United Kingdom is manned by Royal Air Force personnel only. The United Kingdom exercises limited participation, but its fleet of E-3D aircraft is an integral part of the NAEW&C Force.

With regard to the NAEW&C Force, the Force Commander conducted a comprehensive Force Review that determined the size and shape of the Airborne Warning & Control System (AWACS) capability for the future, adapting it to match the new personnel ceilings decided in the context of the new command structure. On this basis, Allies committed to the modernisation of NATO AWACS, extending the fleet’s life until 2035, after which additional lifetime extensions are no longer practical.

NATO’s Alliance Ground Surveillance (AGS) system provides SACEUR the capabilities for near real-time, continuous information and situational awareness concerning friendly, neutral, and opposing ground and surface entities. The AGS system consists of five NATO RQ-4D “Phoenix” remotely piloted aircraft, associated ground command and control stations, and support facilities provided by the AGS’ main operating base at Sigonella, Italy. Using advanced radar sensors, these systems can continuously detect and track moving objects and provide radar imagery of areas of interest and stationary objects. AGS contributes to a range of missions such as the protection of ground troops and civilian populations, border control and maritime safety, the fight against terrorism, crisis management and humanitarian assistance in natural disasters.



Supreme Headquarters Allied Powers Europe (SHAPE) was activated on 2 April 1951, in Rocquencourt, France, as part of an effort to establish an integrated and effective NATO military force. Allied Command Atlantic (ACLANT), headed by Supreme Allied Commander Atlantic (SACLANT), was activated a year later, on 10 April 1952.

In 1967, after France's withdrawal from NATO's integrated military structure, SHAPE was relocated to Mons, Belgium.

The London Declaration of July 1990 was a decisive turning point in the history of the Alliance and led to the adoption of the new Alliance Strategic Concept in November 1991, reflecting a broader approach to security. This in turn led to NATO's Long Term Study to examine the Integrated Military Structure and put forward proposals for change to the Alliance's force structures, command structures and common infrastructure.

In essence, the Cold War command structure was reduced from 78 headquarters to 20 with two overarching Strategic Commanders, one for the Atlantic, and one for Europe; there were three Regional Commanders under Supreme Allied Commander Atlantic (SACLANT) and two under Supreme Allied Commander Europe (SACEUR).

During the 2002 Prague Summit, NATO’s military command structure was again reorganised with a focus on becoming leaner and more efficient. The former Allied Command Europe (ACE) became Allied Command Operations (ACO). Supreme Allied Commander Europe and his staff at Supreme Headquarters Allied Powers Europe (SHAPE) situated in Mons, Belgium, were henceforth responsible for all Alliance operations, including those previously undertaken by ACLANT. At the same time, the former Allied Command Atlantic became Allied Command Transformation (ACT), with different functions. The reform resulted in a significant reduction in headquarters and Combined Air Operations Centres – from 32 command centres down to nine – and reflected a fundamental shift in Alliance thinking.

In 2010, the decision was taken to conduct a far-reaching reform of the NATO Command Structure as part of an overall reform of NATO. The reform was conducted with the development of the 2010 Strategic Concept firmly in mind and focused on ensuring that the Alliance could confront the security challenges of the 21st century effectively and efficiently. The command structure is forward-looking and flexible, as well as leaner and more affordable. In comparison to the previous structures, it provides a real deployable, multinational command and control capability at the operational level.

The current command structure was approved by NATO defence ministers in June 2011 and transitioned to its current format (Transition Day) on 1 December 2012. Building on these achievements, more reforms were initiated in June 2011 to further increase the flexibility of ACO and provide a deployable command and control (C2) capability at the operational level, offering choices and options for rapid intervention that were not previously available to the Alliance. Moreover, a Communication and Information Systems (CIS) Group was formed as part of the military command structure to provide additional deployable communication and information systems support. The reform led to an estimated reduction in personnel of approximately 30 per cent (from 13,000 to 8,800). The military command structure was downsized from 11 entities to 71 .

In 2017, NATO defence ministers agreed on an outline for future work to adapt the NATO Command Structure to new challenges and in June 2018, they agreed to:

  • a new command for the Atlantic, based in Norfolk, Virginia, in the United States, to ensure that sea lines of communication between Europe and North America remain free and secure;
  • a new command to improve the movement of troops and equipment across Europe, based in Ulm, Germany; and
  • a new cyberspace operations centre to strengthen cyber defences and integrate cyber capabilities into NATO planning and operations based in Belgium.

Furthermore, at the meeting of NATO defence ministers in October 2020, Allies decided to create a NATO Space Centre to support NATO missions with communications and satellite imagery, share information about potential threats to satellites, and coordinate activities in this crucial domain. The Centre is located at Allied Air Command in Ramstein, Germany.


  1. These figures cover Allied Command Operations and Allied Command Transformation.