TEL AVIV, Israel When an Israeli mother of three was killed yesterday in a drive-by shooting in the West Bank, U.S. Consul Ronald Schlicher, the Jerusalem-based diplomat who maintains U.S. contacts with Palestinian leaders, quickly called Yasser Arafat to ask what he was going to do about it.

Arafat, desperately trying to remain in the Bush administration"s good graces, said his Palestinian Authority"s security services would hunt down and arrest the perpetrators, U.S. sources said.

The incident reflected Washington"s determination to keep alive the tenuous calls for a truce issued Tuesday by Arafat and Prime Minister Ariel Sharon of Israel. It also was the latest example of serial U.S. efforts to pressure Arafat and Sharon to get new peace talks underway in hopes of making it easier for Arab governments to join President Bush"s campaign against terrorism.

But the killing yesterday morning of Sarit Amrani, 25, near the West Bank settlement of Tekoa constituted a severe challenge to the U.S. goal. Sharon called for a security meeting late yesterday night to discuss whether to maintain his restriction on offensive Israeli military actions. He and his spokesmen made it clear that, in their view, Arafat has not kept his word to end violence.

"I am very sorry that the Palestinian Authority is not keeping its commitments,"" Sharon said early in the day.

After nightfall, the Israeli army reported numerous shooting incidents, hand-grenade attacks on Israeli outposts in the Gaza Strip and the detonation of a roadside bomb as a military vehicle passed.

For the time being, the United States was reserving judgment. "If the shooting was an aberration, then it will fade away. If not, it means Arafat is not serious, and a negative scenario is in play: a higher level of violence,"" said a Western diplomat.

Since the Sept. 11 suicide attacks on New York and Washington, Secretary of State Colin Powell has intervened numerous times to persuade Arafat and Sharon to stop the clashes that have raged here for almost a year. He has made 19 telephone calls spread among Arafat, Sharon and Israeli Foreign Minister Shimon Peres to promote negotiations.

Powell"s goal is to end the violence and get talks started on security cooperation, the end of Israeli blockades on Palestinian towns and, eventually, Israeli withdrawals from still-occupied parts of the West Bank and Gaza Strip.

So far, Arafat has expressed eagerness to sign onto the U.S. campaign against terrorism, albeit for his own interests, a diplomat here said.

The Palestinian leader wants to avoid being seen by the United States as on the "wrong side"" of the terrorist divide, inviting a heavy assault from Sharon in the name of fighting a global scourge. Arafat has indicated he will rein in Islamic militant groups that have initiated terrorist assaults inside Israel. But from the U.S. point of view, that is not enough. Diplomats are pressuring himalso to curb military attacks on Israeli soldiers and settlers by Fatah, the main component of Arafat"s Palestine Liberation Organization.

Members of two Palestinian Authority forces in Bethlehem, Force 17 and the Preventive Security Unit, said they have been ordered to prevent firings on Israeli targets, but that persuasion was their main method. They are supposed to make arrests only as a last resort.

This soft approach seems to suggest Arafat fears repercussions of cracking down hard. Many Palestinians considered the attacks on Washington and New York as, at least, a due lesson in the kind of suffering that has long afflicted Palestinians.

Some rejoiced when they heard the news.

In any case, Arafat also appears to be trying to keep a lid on Palestinian passions by suppressing news of Palestinian casualties. On Wednesday, a Force 17 member was shot in the head at his post in the West Bank town of Hebron. Overnight, a farmer in the Jordan Valley was also found dead on his land. Normally, Palestinians would have declared both as martyrs to the cause, no matter what the circumstance of death. Instead, no Palestinian media have publicized the incidents.

Sharon, meanwhile, has resisted the Bush administration"s contention that the attacks on the United States provide a reason to move ahead on peace talks. Such thinking lets Arafat off the hook for promoting a year of violence, he has told the administration. I don"t think Sharon sees this as an opportunity. He sees it as a problem,"" the Western diplomat said.

The Bush administration has had numerous diplomatic run-ins with Sharon in the past nine days. Powell opposed Israel"s invasions of areas formally under Arafat"s control. Last Friday, Sharon rebuffed Bush"s call for swift talks between Peres and Arafat.