JERUSALEM - With Israel's construction freeze on Jewish settlements in the West Bank scheduled to end this weekend, Israeli and Palestinian negotiators were seeking an elusive formula Wednesday to keep their new peace talks going while both sides warned that if the talks ended, violence could erupt.

As if to illustrate that warning, Palestinians clashed with Israeli security forces in and around the Old City of Jerusalem after an Israeli security guard fatally shot a Palestinian resident of Silwan, a contested east Jerusalem neighborhood where a few hundred Jewish settlers live among tens of thousands of Palestinians.

The guard told police that he had opened fire in self-defense after being ambushed by stone-throwers before dawn. But Palestinians said there were signs that the dead man, Samer Sirhan, 32, had been chased by the guard, and Palestinian spokesmen accused the Israeli settlers of carrying out provocations to divert attention from the issue of Israeli settlement construction.

Sirhan, a father of five, was a member of Fatah, the mainstream Palestinian party engaged in the peace talks with Israel.

The Palestinian leadership has said that the 10-month building moratorium that ends Sunday must be extended for the talks to progress and that if settlement construction started again next week, it would prove that the Israeli government was not serious about making peace.

A question of sincerity?

The government of Prime Minister Benjamin Netanyahu has responded that such talk is evidence of Palestinian insincerity, saying that the moratorium was a gesture aimed at making it easier for the Palestinians to enter direct talks. Since they waited nine months before taking advantage of it, walking out on the talks now would prove that they were not serious about peace, Israeli officials maintain.

Efforts by the Obama administration to get Netanyahu to extend the freeze by three months have not succeeded.

"The end of the freeze is a test case for the concept of compromise," Dan Meridor, Israel's minister for strategic affairs, said this week. "Neither side will get all it wants."

Palestinian Authority President Mahmoud Abbas has often said that once building resumed, he would end the peace talks. But Tuesday, he spoke to U.S. Jewish leaders in New York and did not insist that the end of the construction freeze meant the end of the talks. "I cannot say I will leave the negotiations, but it's very difficult for me to resume talks if Prime Minister Netanyahu declares that he will continue his activity in the West Bank and Jerusalem," he told the leaders.