Pope Francis has asked for prayers so that participants at a humanitarian summit in Turkey fully commit to achieve what he defines as their main aim: saving the life of every human being.

Francis addressed tens of thousands of tourists and pilgrims in St. Peter's Square Sunday and expressed his hopes for the summit which opens the next day in Istanbul.

He noted that the first such world summit aims to reflect on which measures should be adopted to deal with "dramatic humanitarian situations caused by conflicts, environmental issues and extreme poverty."

He invited prayers so that the summit will yield a commitment to "save the life of every human being, no one excluded, especially the innocents and most defenseless."

Francis' secretary of state will attend the summit.