Pope Francis on Sunday sent prayers to the victims of the concert hall attack in Moscow, calling the violence “inhuman acts” that offended God.

“I assure you my prayers for the victims of the cowardly terrorist attack carried out the other evening in Moscow,” said the 87-year-old pope, following a Palm Sunday mass in Saint Peter’s Square.

“May the Lord welcome them in his peace and comfort their families, and convert the hearts of those... who organize and carry out these inhuman actions which offend God, who commanded ‘Thou shalt not kill.’”

The Pontiff presided over Palm Sunday Mass in front of a crowd the Vatican estimated at 25,000 people but spoke in a weak, faltering voice and did not deliver his homily as planned.

Following the mass, he appeared in good spirits; however, he circled the piazza, smiling and waving at the crowd from his vehicle.

Francis caught the flu last month and has subsequently asked others to read his texts at appearances. He has suffered from several health issues in recent years, from knee and hip pain to an inflamed colon and hernia surgery last year.