IZNIK, Turkey, Dec. 26 (AP) - As festivities surrounding the 2,000th anniversary of Christ's birth drew to a close, Orthodox Christian leaders from around the world gathered at an ancient, crumbling church Tuesday to call for greater unity among the world's Christians.

Meeting in the place where early Christians first spelled out the creed that still binds them, they called on the faithful to work together to heal the rift that split the Christian church into the Orthodox and Roman Catholic branches in 1054.

``The Christian world was divided and fragmented, lamentably, to the great scandal of the whole world,'' said a statement signed by the spiritual leader of the world's Orthodox Christians, Ecumenical Patriarch Bartholomew I, and representatives of 14 Orthodox churches. ``We invite everyone to work in a dialogue of truth and love for the unity of those who believe in Christ.''

In addition to Istanbul-based Bartholomew I, the statement was signed by representatives of the churches in Alexandria, Antioch, Jerusalem, Serbia, Romania, Bulgaria, Georgia, Cyprus, Greece, Poland, Albania, the Czech Republic and Slovakia, Finland and Estonia. It was issued during a religious service at the Church of Hagia Sophia in this small city - also known as ancient Nicaea - south of the Sea of Marmara in western Turkey.

Bitterly cold winds blew through the site - now a collection of walls turned into a museum - as the bearded patriarchs chanted and prayed in their vestments of golden brocade.

The Byzantine-era church was the gathering place for representatives of Christian churches who formed the Seventh, and last, Ecumenical Council in 787. The councils are important in church history because they defined the tenets of belief.

The First Ecumenical Council in 325 - also held in Nicaea - spelled out the Christian faith in a creed. Named for the site, the Nicene Creed is still a centerpiece of today's Orthodox and Roman Catholic liturgies.

On Tuesday, the leaders called for greater unity between Orthodox and other Christians as well as among the Orthodox churches of different nations.

``We have at other previous synaxes (assemblies) such as these strongly condemned schisms that plague the unity of the Most Holy Orthodox Church,'' read the statement. ``Once again we invite all those who for whatever reason have separated from the canonical structure of the church to return to it.''

But attempts at Orthodox unity have stumbled as badly as efforts to heal the nearly 1,000-year rift with the Roman Catholics.

Patriarch Alexy II of Russia - leader of the largest Orthodox Church - did not attend the current meeting in Turkey, the first of its kind since 1995. Alexy, who also boycotted the 1995 meeting, is still irked by Bartholomew's 1996 recognition of the autonomy of the Estonian church after it broke off from Moscow. He fears the Ukrainian Orthodox could ask the same from Bartholomew's ecumenical seat.

On Monday, the patriarchs co-celebrated a Christmas service at the Greek Orthodox Cathedral of St. George in Istanbul, which the Orthodox still refer to as Constantinople, its pre-Islamic name.