In a meeting with U.S. envoy George Mitchell in Ramallah on Tuesday, Palestinian President Mahmoud Abbas expressed his disappointment with the United States for failing to declare that talks on borders with Israel will be based on 1967 lines.

Abbas said he was upset that Mitchell insisted that border negotiations won't necessarily be based on 1967 lines, a term former prime ministers Ehud Barak and Ehud Olmert committed to in the past.

The Palestinians told Mitchell that Abbas has already submitted a document to the United States in the spring detailing the Palestinian stance on all the core issues. They emphasized that their stance hasn't changed, and that the U.S. must demand terms from Prime Minister Benjamin Netanyahu, not them.

Abbas also expressed his disappointed that the U.S. criticized the countries that recognized an independent Palestinian state, saying that there is no clause in the talks with Israel that prevents this move. They emphasized that they already made a declaration of an independent Palestinian state in 1988.

The Palestinians also noted that the Arab League intends to push forward a UN resolution on establishing a Palestinian state, as well as a resolution which will declare the West Bank settlements illegal.

Chief Palestinian negotiator Saeb Erekat said following Mitchell's meeting with Abbas that "any negotiations or talks require an end to settlement activities."

A source close to Abbas told AFP prior to the meeting that the Palestinian leader wanted "guarantees and answers" from Washington before he would agree to return to peace negotiations with Israel.

The source said Abbas hoped to receive a response from Mitchell during their talks regarding a letter dispatched from chief Palestinian negotiator Saeb Erekat to U.S. Secretary of State Hillary Clinton last week, in which the prior requested "guarantees and answers before returning to any negotiations, direct or indirect".

The letter reportedly presents two key conditions for resuming negotiations: that the U.S. ensure a "complete halt" to Israeli construction in the West Bank and East Jerusalem, and that it agrees to recognize a Palestinian state based on 1967 borders.

Failing a U.S. guarantee to these requests, the source told AFP, the Palestinians are asking U.S. President Barack Obama to refrain from moving against United Nations' recognition of a Palestinian state along these borders.

Mitchell held a three-hour meeting with  Netanyahu in Jerusalem on Monday, days after Washington dropped its offer for a package of incentives in exchange for a temporary Israeli settlement freeze in the West Bank.

Prior to that meeting, the envoy reiterated Clinton's declaration that the Obama administration was intent on reaching a peace agreement and hoped to restart indirect talks to achieve that goal.

During his separate talks with the Palestinian and Israeli leaders, Mitchell apparently shifted the focus of discussion toward core issues. He had been expected make clear to Netanyahu that the Obama administration wanted him to take a clear stance on these issues, with an emphasis on borders.

Associates of Netanyahu called the meeting with Mitchell "positive"; the prime minister declared following their talks that he was "prepared to discuss all of the fundamental issues" necessary for resuming negotiations with the Palestinians and reaching a peace agreement.