The head of the Ukrainian Greek Catholic Church (UGCC) has condemned a “horrifying” alleged Russian attack that struck a children’s hospital in the Ukrainian capital of Kyiv.

A Monday press release on the UGCC’s website said that Russian forces had “launched a massive missile attack” that resulted in hits on the Okhmatdyt Children’s Hospital as well as “a private maternity hospital in Kyiv.”

UGCC Head and Archbishop Sviatoslav Shevchuk said in a video accompanying the release that the strike was “a sin that cries to heaven for vengeance.”

“It is horrifying to see that the children who came to save their lives in the artificial kidney center were ruthlessly killed by Russian criminals,” the prelate said in the release. 

Russia has denied responsibility for the attack.

The bishop said that many of the children in the hospital “were on the verge of death” at the time of the strike, according to the news release, with many “undergoing surgery at the time.”

“In the name of God, with all our resolve, we condemn this crime against humanity,” the archbishop said. 

Rescue workers were still clearing the rubble, Archbishop Sviatoslav said, but “we already know about dozens of dead and around a hundred injured.”

First responders were “standing in a chain and dismantling stones to save more children whose hearts are beating under the rubble,” he said.

The prelate described the strike as “not only a crime against human laws and … international rules of warfare” but also “a sin that cries for vengeance to heaven, according to Christian morality.”

“Today we cry with all the victims, we pray for all the perished, especially the innocent children,” Archbishop Sviatoslav said. “We want to wrap all the wounded with our Christian love, all those who are hurting the most.”

“Lord, by Your power, instill in us hope for the protection of the lives of our children and women. Merciful God, bless our long-suffering Ukrainian land with Your just peace!” the archbishop said.

The Russian government, meanwhile, denied responsibility for the attack, with Kremlin spokesman Dmitry Peskov telling media on Tuesday that the country’s military does not target civilian structures. 

Peskov alleged that the strike was instead caused by “a falling anti-missile system” used by Ukraine.