President Volodymyr Zelenskiy called on his fellow Ukrainians on Orthodox Easter on Sunday to unite in prayer for each other and the soldiers on the frontline, saying God -- who has a "Ukrainian flag on his shoulder" -- will lead to life defeating death.

"Let's pray for each other. When we all came closer to each other, we were no longer strangers to each other," Zelenskiy, dressed in a traditional embroidered Ukrainian shirt -- vyshyvanka -- and his typical khaki pants, said in a lyrical video posted on the Telegram messaging app.

Standing in front of the 1,000-year-old Saint Sophia Cathedral in Kyiv, a spiritual and architectural monument of the country's faith, Zelenskiy said that Ukraine has now been fighting for 802 days against Russia for a victory.

"And we believe: God has a chevron with the Ukrainian flag on his shoulder. So with such an ally, life will definitely win over death."

Orthodox Christians, including the Orthodox Church in Ukraine and Russia, celebrate Easter this weekend, while most Western churches observed the major holiday on March 31.

In Moscow, President Vladimir Putin attended an Easter service led by the head of Russia's Orthodox Church, Patriarch Kirill, a staunch supporter of the Russian leader and his war in Ukraine.

Tens of thousands have been killed and millions driven from their homes since Putin ordered the invasion of Russia's smaller neighbour in February 2022. The war, now in its third year has no end in sight.

Zelenskiy, who is Jewish, called for prayers first for all the soldiers who will be celebrating Easter in the trenches, so they will return home alive, and for the land and people, whose spirit "cannot be broken" and who will, he added, see Ukraine free one day.

"Ukrainians kneel only in prayer," Zelenskiy said. "And never before invaders and occupiers."

(Writing by Lidia Kelly in Melbourne; Editing by Kim Coghill)