The top Palestinian negotiator, Saeb Erekat, has quit his post on the eve of crucial talks with Israel.

Palestinian officials say Mr. Erekat was enraged when he was left out of the delegation that will meet Saturday with the Israeli Prime Minister, Ariel Sharon.

The delegation will be headed by the new Palestinian Prime Minister, Mahmoud Abbas, and the talks will be the highest level contacts between the two sides in more than two years.

The Palestinian delegation also includes the Palestinian Security Minister, Mohammed Dahlan and the Speaker of the Palestinian parliament, Ahmed Qurei'a.

But Mr. Abbas pointedly excluded Mr. Erekat, the minister responsible for peace negotiations with Israel. In protest, Mr. Erekat handed in his letter of resignation.

Mr. Erekat refused to comment on the matter, saying it was an internal Palestinian affair.

Mr. Abbas has reportedly asked Mr. Erekat to allow him one week to respond to the resignation letter.

Mr. Erekat has been a leading Palestinian negotiator since peace talks between Israelis and Palestinians were first launched at Madrid in 1992.

He is also a known loyalist of the Palestinian president, Yasser Arafat, who only reluctantly agreed to share power with the Prime Minister, following intense pressure from abroad.

Mr. Arafat has reportedly asked Mr. Erekat to reconsider his decision.

Meanwhile, Mr. Sharon met Friday with his key advisors to prepare for the meeting with the Palestinian delegation.

Palestinian officials say they want assurances from Israel that it is prepared to start implementing the "road map" to peace plan that calls for the establishment of a Palestinian state by 2005.

The Israeli Justice Minister, Tommy Lapid, who was to join the talks on Saturday, says he wants the Palestinians to demonstrate they are serious about halting violence and terrorism.

Mr. Lapid defended Israel's decision to launch a military raid inside Beit Hanoun in the northern Gaza Strip, in a bid to stop more Palestinian rocket attacks.

At least five Palestinians have been killed in the operation, which began on Thursday.

Mr. Lapid says that it will be difficult to make political concessions to the Palestinians, while the rocket attacks continue.