U.S. peace envoy to the Middle East George Mitchell arrived on Friday in the West Bank city of Ramallah and immediately held talks with Palestinian President Mahmoud Abbas, official Palestinian sources said.

The sources said that Mitchell met with Abbas to follow up the U.S.-sponsored proximity talks, which were officially launched between Israel and the Palestinians on May 9.

Meanwhile, Yasser Abed Rabbo, a Palestine Liberation Organization (PLO) official, said in a statement that President Abbas is awaiting to hear the Israeli answers that Mitchell is carrying with him.

"We are waiting for the Israeli answers after the Palestinian leadership presented to the American administration specific and detailed ideas related to security and borders. Israel hasn't presented anything," said Abed Rabbo.

He added that the Palestinian leadership wants "a complete Israeli withdrawal, whether it is the Israeli army or the Jewish settlers, from all the occupied territories."

"Security arrangements should be under international observation or in the presence of international forces that protect the borders," said Abed Rabbo.

The United States proposed a four-month proximity talks between Israel and the Palestinians after it failed to bridge the gap of disputes between the two sides, following the Israeli decision to expand settlements.

The Palestinians demand Israel to completely halt all settlement activities in the West Bank and East Jerusalem and resume the talks on final status issues that end with the establishment of an independent Palestinians state.