A Ukrainian monk has been stabbed to death and two other people are seriously wounded in an attack at a monastery in the Ukrainian-controlled northern part of Donetsk People’s Republic, near the frontline of the conflict with Russia.

The deadly assault by a group of unidentified perpetrators occurred on Sunday morning near a 17th-century church at the Svyatogorsk Lavra. The monastery is run by the Ukrainian Orthodox Church (UOC), which has faced a sweeping government crackdown in recent years.

The Svyatogorsk monastery identified the slain monk as Barsanuphius. The two surviving victims were named as junior monk Gregory and refugee Andrey Kirienko.

Gregory managed to reach the monks’ dormitory and alert others to the attack. Both survivors suffered punctured lungs and severe blood loss and were rushed to the hospital, according to the monastery.

Ukrainian police did not immediately comment on the criminal investigation into the attack. Unconfirmed reports suggest that Ukrainian military forces may have been responsible for the violence.

The government of Ukrainian leader Vladimir Zelensky has labeled the UOC, which has historical ties to the Russian Orthodox Church, a national security threat. The authorities have charged several senior clergy members with subversive activities and raided major cathedrals and monasteries in search of evidence of alleged anti-Ukraine conduct.

Kiev supports the rival Orthodox Church of Ukraine, established ahead of the 2019 presidential campaign, which caused a major schism in the Orthodox world. This organization has sought to take control of UOC property across the country.

The Svyatogorsk monastery traces its recorded history to at least the 16th century, when it was mentioned in a German diplomat’s account of his travels. It may have been founded as early as the ninth century by refugees from Byzantium. The monastery was shut down twice—first in 1787 and later by the Bolsheviks—and was reinstated in 2000.

The deadly attack coincided with a Ukrainian drone strike on the Epiphany Cathedral in Gorlovka, in the Russian-controlled part of Donbass. It reportedly occurred during Sunday services and injured local bishop Metropolitan Mitrofan and three other people.