Updated

RAMALLAH, West Bank (AP) — President Barack Obama warned Mahmoud Abbas in a letter that U.S.-Palestinian relations might suffer if the Palestinian leader refuses to resume direct peace talks with Israel, a senior PLO official said Saturday.

The White House had no comment Saturday. However, the Obama administration has been pushing Abbas hard in recent days to move quickly to face-to-face negotiations.

The PLO official said Obama sent the letter — the strongest U.S. warning to Abbas yet — on July 16.

Abbas insists he will only negotiate once Israel commits to the idea of a Palestinian state in the West Bank, Gaza and east Jerusalem, with minor modifications. He also wants Israel to freeze all settlement construction in those areas.

Israeli Prime Minister Benjamin Netanyahu refuses to be pinned down ahead of talks and has put in place only a 10-month freeze in housing starts in the West Bank that is due to expire in September.

Earlier this week, senior Palestine Liberation Organization members were briefed on the latest attempts to restart talks. During the meeting, an Abbas aide summarized the main points of Obama's letter, said the PLO official, who spoke on condition of anonymity because the letter has not been made public.

"In this letter, Obama asked Abu Mazen (Abbas) to go to direct negotiations and (wrote) that he can't help the Palestinians unless they go to direct negotiations," the official said. "Obama said he expects Abu Mazen to agree to this demand, and that not accepting it would affect the relations between the Palestinians and the Americans."

Chief Palestinian negotiator Saeb Erekat insisted the letter did not refer to Palestinian-U.S. ties. Erekat said Obama wrote that he remains committed to establishing a Palestinian state, but that his ability to help will be limited if Abbas does not resume negotiations.

Negotiations between Abbas and Netanyahu's predecessor broke off in December 2008.

Palestinians are wary of resuming talks with the hardline Netanyahu without reaching agreement first on an agenda, a timetable and a framework. Netanyahu has said he is eager to negotiate, but has refused to pick up where the last round left off and has said he will never relinquish east Jerusalem, the Palestinians' hoped-for capital.

Since early May, White House envoy George Mitchell has been shuttling between Abbas and Netanyahu. Such indirect talks were to last for up to four months. Abbas' aides have said they want the indirect talks to run their course before deciding whether to move to direct negotiations, but the White House wants to move to face-to-face talks now.

On Thursday, Arab foreign ministers meeting in Cairo endorsed the idea of direct negotiations, but left the timing up to Abbas.

On Monday, the PLO's top decision-making body, the Executive Committee, will be asked to make a recommendation.

"The Palestinians are between a rock and a hard place," said committee member Hanan Ashrawi.

She said public opinion in the Palestinian territories opposes talks without ironclad guarantees, but that Abbas would be blamed by the world if negotiations don't get off the ground.

The push for peace talks came at a time of renewed violence on the Gaza-Israel border.

On Friday, Gaza militants fired a rocket at the Israeli coastal city of Ashkelon, causing damage but no injuries.

Israel retaliated with a series of airstrikes that killed a senior commander of the Hamas military wing and wounded 11 people. Hamas said it would avenge the death of the commander, 44-year-old Issa Batran.

Late Saturday, Gaza militants fired a rocket at an Israeli border community, damaging a building, but causing no injuries.

The violence came after weeks of relative calm and raised concerns of further escalation.