Pope Francis is praying that a "merciful" God will touch the hearts of those in Syria who have abducted Catholic and Orthodox faithful, including bishops and priests, so that the captives will be released soon.

Francis told tens of thousands of people in St. Peter's Square where he celebrated Mass Sunday that he was very concerned about those held captive in Syria, which has been ravaged by five years of civil war.

The pope didn't cite any particular hostage by name. He also appealed for prayers for all persons held kidnapped in the rest of the world.