Orthodox Christmas services got under way Friday as worshippers across the world prepared to commemorate the birth of Jesus Christ.

Many Orthodox Christians, including Russians, Greeks, Serbs and Montenegrins, celebrate Christmas on January 7, according to an older calendar.

Political leaders join citizens in religious services, including in former communist countries, such as Russia.

Tradition also calls for a 40-day fast before Christmas, during which the pious do not eat meat, dairy products or eggs. The fast ends at midnight and gives way to sumptuous feasts, but those should not start before one has attended a religious service.

Some Christians in southern and eastern Europe marked the feast of Epiphany Friday, a religious holiday celebrating the revelation of God as man. Young men in Bulgaria dived in cold waters in a contest to retrieve a cross. According to belief, the person who captures it will be freed of evil spirits or other troubles.

In Romania, tradition calls for the blessing of domestic animals as well as people at Christmas.

In some countries, including Bosnia-Herzegovina and Serbia, the Orthodox Christmas Eve tradition requires cutting branches from oak trees, to be burned later in huge fires in front of churches and at home.

The fires are believed to warm the community with love and harmony.

Serbian President Boris Tadic sought to contribute to the spirit of Christmas by sending a message of peace to Albanians as well as Serbs in neighboring Kosovo. But on his way to a religious service Friday in an ancient Serbian monastery in Kosovo , angry Albanian protesters hurled stones at his armored motorcade.