Pope Francis prays at Bethlehem wall

Pope Francis makes a surprise stop at the wall Palestinians see as a symbol of Israeli oppression.

It's an image set to become one of the most emblematic of his trip.

He stood at a spot where someone had sprayed in red paint "Free Palestine." Above his head, graffiti in broken English reading: "Bethlehem look like Warsaw Ghetto"

Israel says the barrier, erected 10 years ago during a series of Palestinian suicide bombings, is needed to secure its security. Palestinians see it as a bid by Israel to partition off territory and grab land they want for their future state.

At a mass in Bethlehem he invites the Israeli and Palestinian presidents to come to the Vatican to pray for peace.

(SOUNDBITE) (Italian) POPE FRANCIS SAYING:

"In this place where the Prince of Peace was born, I wish to direct an invitation to you Mr. President Mahmoud Abbas and to Mr. President Shimon Peres to hold together with me an intense prayer to invoke from God the gift of peace.