Pope Francis landed in the West Bank town of Bethlehem on Sunday at the start of a two-day tour of the Palestinian territories and Israel.

The pontiff arrived in a Jordanian military helicopter which touched down at a helipad in the town which is revered as the birthplace of Jesus, and where he was to hold a public mass later in the morning.

His arrival in the West Bank, after beginning his trip in Jordan on Saturday, marks the start of the most sensitive part of his three-day Middle East tour aimed at forging regional peace and easing an age-old rift within Christianity.

Although Francis himself has said it will be a "purely religious trip," both Israel and the Palestinians will be looking to use the visit to score a few political points.

After meeting Palestinian president Mahmud Abbas, the crowd-loving pope will drive through Bethlehem in an open-top car to Manger Square where he will give a mass that will be attended by nearly 10,00 people.

Meanwhile in Jerusalem, police arrested 26 Jewish extremists protesting at a key holy site on Mount Zion where the pope will hold a mass on Monday.