UN Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Valerie Amos arrived in Jerusalem for a four-day tour to the occupied Palestinian territory and Israel. She is expected to meet with members of the Palestinian leadership and also hopes to meet with Israeli authorities.

She spoke just one day before Palestinians are expected to commemorate the Nakba - translated as "catastrophe" in Arabic - which commemorates the displacement of hundreds of thousands of Palestinians in warfare that led to the establishment of Israel in 1948. More than 700,000 people fled or were forced from their homes during the fighting.

Large demonstrations took place in the West Bank, Jerusalem and in other parts of Israel on May 14 to mark the day. In advance of the commemoration, the Israeli military closed West Bank crossings.

For the past two days, military checkpoints along the Sinai have been turning back hundreds of pro-Palestinian activists intending to demonstrate on May 15 at the Egypt-Gaza border.

On Friday, about 6,000 Palestinian refugees gathered near Jordan's border with Israel to demand to return to their ancestral homes. Organizers of that rally said the demonstration last through to MaY 15 to coincide with the start of the so-called third intifada.