"Odesa: another night attack of the monsters," Oleh Kiper, governor of southern Ukraine's Odesa region, said on the Telegram messaging app.
Odesa's military administration said that the Spaso-Preobrazhenskyi Cathedral of the Moscow-linked Ukrainian Orthodox Church (UOC), was severely damaged.
The Spaso-Preobrazhenskyi Cathedral, or the Transfiguration Cathedral, is Odesa's largest Orthodox church building.
Ukraine has accused the UOC of maintaining links to the pro-invasion Russian Orthodox Church, which used to be its parent church but with which the UOC says it broke ties in May last year.
Social media videos showed a distressed man walking inside the dark cathedral repeating, "The church is no longer .... Lord, have mercy."
Persons:
Kiper, God, Gleb Garanich, Lidia Kelly, Paul Simao, Richard Chang
Organizations:
Sunday, Church, Odesa, Reuters, Russia, Onyx, Thomson
Locations:
Odesa, Ukraine's, Russia, Preobrazhenskyi, Moscow, Ukraine, Russian, Crimea, Ukrainian, Kyiv, Melbourne