Nato welcomed Albania and Croatia yesterday as the 27th and 28th members of the military alliance, after their ambassadors filed their instruments of accession with the US government.
The move, held up by a border dispute between Croatia and Slovenia, paves the way for Albania - first in alphabetical order among Nato allies - to take a seat next to Nato's secretary general at a summit starting tomorrow.
"Today, Albania and Croatia have completed the accession process, and have joined the alliance as members," Nato Secretary General Jaap de Hoop Scheffer said in Brussels, where the North Atlantic Treaty Organisation is based.
"I warmly congratulate them on this historic achievement. In becoming Nato members, Albania and Croatia share the benefits and responsibilities of collective security," he said in a statement.
Earlier, Albanian Ambassador Aleksander Sallabanda and Croatian Ambassador Kolinda Grabar-Kitarovic represented their countries at the ceremony in Washington hosted by US Deputy Secretary of State James Steinberg.
"The Republic of Croatia has fulfilled one of its two foreign policy targets: to join the European Union and Nato," President Stipe Mesic was quoted as saying by state-run HINA news agency.
"Today, the first of those goals has been achieved, we are becoming a full member of the Nato alliance and, by doing so, we have ensured security for our country."
Albania and Croatia already have troops in Afghanistan, where Nato is fighting its biggest and most complex mission trying to stem a worsening Taliban-led insurgency.
Nato spokesman James Appathurai told reporters that the two countries had "worked very hard to meet alliance standards with regard to democracy, with regards to the state of their militaries.
"They have overcome what was a difficult period in Balkans history not too long ago, to become contributors to regional stability and to international security through Nato already."
They will be officially welcomed tomorrow by Nato's leaders, meeting for a two-day summit in Strasbourg, northern France and neighbouring Kehl in Germany, to focus on future security challenges and missions in Afghanistan and Kosovo.
The two Balkans states were only able to join after Slovenia filed documents with the United States endorsing them as members. Slovenia took the action on Croatia's behalf on Monday after doing the same for Albania on March 3.
Slovenia and Croatia are involved in a long-standing border dispute that has already stalled Croatia's EU accession process. But Slovenia insisted that the row did not effect Zagreb's Nato bid.
After Greece ratified Croatia's accession in mid-February, Slovenia was the last of the 26 Nato members not to have handed the alliance its signature.