Greece and Turkey have backed Romania and Bulgaria's NATO bids, pledging to help bring the Balkan neighbors in the alliance.
The foreign ministers of long-time NATO members Greece and Turkey said the admission of the two countries will boost European stability and NATO security.
The statement follows a meeting in Istanbul of the foreign ministers of the four countries. They were in the Turkish city for a summit of Islamic and European nations to bridge the gap between the Muslim and Western worlds.
Bulgaria and its northern neighbor, Romania, are among nine former-Communist states in eastern Europe applying for NATO membership.
Though lagging behind other contenders, the two Balkan countries have stepped up efforts to improve their political, economic and military standards to match those of NATO members.