United States president George Bush has signed North Atlantic Treaty Organisation (NATO) agreements which put Albania and Croatia a step closer to joining the western security alliance.
NATO members agreed at an April summit in Bucharest to invite Albania and Croatia to join.
The Balkan neighbours will be eligible when all 26 NATO members ratify the accession protocols.
Mr Bush described it as an historic step for the Balkans.
"In the space of a single decade this region has transformed itself from a land consumed by war to a contributor to international peace and stability," he said.
Mr Bush also reaffirmed US support for NATO membership for Georgia, Ukraine, Bosnia-Herzegovina and Montenegro, and for Serbia if it chose that path.