JERUSALEM — Moments after Secretary of State Colin Powell called for an end to the Palestinian-Israeli conflict here on Friday, a Palestinian sniper shot and killed an Israeli motorist on a West Bank road.

The Palestinian resistance group Hamas — which Powell had just labeled "an enemy of peace" — claimed responsibility for the attack.

Powell's visit here is aimed at stemming the bloody tide and rescuing a peace plan for the region backed by President Bush. Powell is scheduled in Jordan on Sunday to meet with officials from Russia, the European Union and the United Nations — the other international authors of the so-called "road map" to peace.

At a joint news conference with Israeli Prime Minister Ariel Sharon, Powell said that Palestinians and Israelis "face a moment of great opportunity but also a time of great challenge. . . . Terror must not be, will not be, allowed to deter us . . . The pace and urgency of our work needs to be maintained."

The "road map" is a plan of reciprocal confidence-building measures designed to restart Israeli-Palestinian peace talks. The multiphase plan kicked off with a summit attended by President Bush, Sharon and Palestinian Prime Minister Mahmoud Abbas in Aqaba, Jordan, on June 4. It was met almost immediately with a devastating cycle of violence.

Killed in Friday's ambush on Route 60 near the West Bank Jewish settlement of Ofra was 47-year-old, Brooklyn-born Zvi Goldstein, who emigrated to Israel in 1992. The attack wounded Goldstein's parents, Gene and Lorraine Goldstein, both 73, of Plainview, N.Y., who came to Israel to attend their grandson's wedding Thursday. The family was en route to Jerusalem for a meal when their car was fired upon. Paramedics said two other passengers were hurt when the silver vehicle spun out of control and overturned.

Israeli soldiers searched the area three miles northeast of the Palestinian city of Ramallah but found no immediate signs of gunmen.

Later in the day, in Jericho, the Palestinian-controlled desert oasis outside Jerusalem, Powell met with Abbas. The men talked about a deal in which Palestinian security forces would assume control of parts of the Gaza Strip and the West Bank city of Bethlehem, provided Israeli troops can be persuaded to pull back. Sharon has offered the pullback provided the Palestinian Authority is effective in stopping attacks on Israelis.

"I think that would be a very, very powerful and important first step" after 32 months of non-stop violence, Powell said at a joint news conference with Abbas.

The sight of Palestinian forces reasserting control, Powell said, could cause Gazans to realize that "Hamas and other terrorist organizations perhaps do not have the right answer."

Israel has said Gaza and Bethlehem would be proving grounds for the Palestinian Authority's ability to prevent militants from attacking Israelis.