The Transfiguration Cathedral in the Ukrainian port city of Odesa has been struck by Russian missiles.
The place of worship is a listed by Unesco world heritage site.
Russia claimed targets in Odesa were being used to prepare “terrorist attacks”.
The Kremlin added the hit on the Cathedral was self-inflicted the Ukrainian air defences.
Ukraine’s President Volodymyr Zelensky has vowed retaliation.
“They will definitely feel this,” he warned.
Regional governor Oleh Kiper said 14 people, including four children, were taken to hospital on Sunday after the blasts.
Mr Kiper posted to Instagram:
“Odesa: another night attack of the monsters.”
The UN’s cultural agency, Unesco, has repeatedly urged Russia to cease attacks on Odesa.