Pope Francis has laid out his formula for fostering Christian unity: resist competing for souls and make concrete gestures of acceptance and dialogue.

Francis celebrated vespers Sunday evening in a Rome basilica along with Anglican, Orthodox and other church leaders to cap an annual week of prayer for unity of Christians.

He told the church leaders that "our shared commitment to proclaiming the Gospel enables us to overcome proselytism and competition in all their forms."

Francis said getting to know "those who are different from ourselves can make us grow." He also cautioned about "subtle theoretical discussions in which each side tries to convince the other."

Referring to Christians being persecuted in the Middle East and elsewhere, Francis described their suffering as a kind of "ecumenism of blood."