On 29 March, Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia formally became members of NATO by depositing their instruments of accession with the United States Government.
At 1:00 pm local time, the Prime Ministers of the seven countries handed over their instruments of accession to the North Atlantic Treaty to US Secretary of State Colin Powell, who accepted them on behalf of the United States, which is the depository nation for the Treaty.
The ceremony took place in the Cash Room at the US Department of the Treasury in Washington, D.C.
At that moment the seven countries formally became parties to the North Atlantic Treaty and members of the North Atlantic Treaty Organization. This is the fifth and the largest round of enlargement in NATO's history, bringing NATO to 26 member countries.
The event was celebrated with a special ceremony hosted by United States President George W. Bush at the White House and attended by NATO Secretary General Jaap de Hoop Scheffer.
The accession of the seven new members will be marked by a special flag-raising ceremony at NATO Headquarters in Brussels on 2 April. It will be followed by an informal working luncheon of the Foreign Ministers of the now 26 member countries.