Russian President Vladimir Putin (C) attends the Orthodox Christmas service at the Transfiguration Cathedral in Saint Petersburg, Russia January 7, 2019. (KREMLIN PHOTO)

MOSCOW, Jan. 7 (Xinhua) -- Russian President Vladimir Putin on Monday congratulated all Orthodox Christians and Russian citizens celebrating Christmas by the old Julian calendar, the Kremlin said.

"This wonderful holiday brings people joy and hope, unites them with timeless spiritual and moral values, and the traditions of compassion and charity," Putin said in his greeting message published on the Kremlin's website.

He welcomed the large, positive role that the Russian Orthodox Church and other Christian denominations play in Russian life, and highlighted their contribution to solving pressing social issues and ensuring harmony in interethnic and interreligious dialogues.

"I wish health, success and prosperity to all Orthodox Christians and all Russians celebrating Christmas," Putin said.

The president attended the Christmas service held on the day at the Transfiguration Cathedral in St. Petersburg, which is one of the most visited cathedrals in the city, according to the Kremlin.

Orthodox Christians around the world celebrate Christmas Day annually on Jan. 7 according to the Julian calendar, two weeks after most Western Christian churches do by the commonly used modern Gregorian calendar.