Pope Francis has appealed to faithful to put divisions aside amid persecution and slaying of Christians in parts of the world.

Francis told some 30,000 people in St. Peter's Square today: "The blood of today's martyrs makes us one."

He cited the slaying of 21 Egyptian Coptic Christians by Islamic militants in Libya in February and said "those who hate Jesus Christ ....kill without asking" if the person is Catholic or belongs to another Christian church.

Francis asked: "If the enemy unites us in death, who are we to divide ourselves in life?"

He urged Christians to seek "unity in diversity of expression" through common prayer and charity.

Orthodox patriarchs, Anglican and Lutheran bishops and Evangelical pastors attended the spiritual renewal gathering.

Tenor Andrea Bocelli and others sang "Amazing Grace."