As he has in nearly all of his public appearances since Russia invaded Ukraine last February, Francis appealed for peace at his weekly general audience in the Vatican.

"Last Saturday another missile attack caused many civilian victims, among them children. I share in the heartbreaking pain of the family members," he said.

"The images and the accounts of this tragic episode are a strong appeal to all people of conscience. One cannot remain indifferent," he said.

A total of 45 people have been confirmed killed in the strike.

Ukraine says the apartment building was struck by a Russian Kh-22 missile. The Kremlin said its wave of missile strikes on Saturday did not target any residential buildings.

(Reporting by Philip Pullella; Editing by Angus MacSwan)