Albanian Prime minister Sali Berisha sent a note on Sunday to U.S. President George W. Bush, thanking him for his contribution to getting Albania's NATO accession ratified by Senate.

"We thank you for your contribution towards this, and we will collaborate with all American institutions (on this)," Berisha said in the note of acknowledgment.

The U.S. Senate ratified, along with Croatia, Albania's accession to NATO last Thursday. After the ratification by all 26 NATO parliaments, the two Balkan countries will join the alliance at its next summit in April next year.

Albania and Croatia were invited to join NATO at the alliance's summit in Bucharest, Romania, in early April. In July, the 26 countries of the North Atlantic Council signed the accession protocols of Albania and Croatia.