Updated

Hamas (search) attackers killed an American man Friday and wounded his wife and elderly parents, all Americans, as they drove through the West Bank to a wedding celebration, the militant group said. The shooting underscored the difficulty of ending violence in the region that threatens a U.S.-backed peace plan.

Also Friday, a Palestinian militant was killed in a clash with the Israeli army in the Gaza Strip (search).

Secretary of State Colin Powell (search) met Friday with Israeli Prime Minister Ariel Sharon (search) and Palestinian Prime Minister Mahmoud Abbas (search), pressing them to adhere to the "road map" peace plan, which aims to end nearly 33 months of fighting and create a Palestinian state by 2005.

Violence has endangered the plan since President Bush launched it at a June 4 summit in Jordan with Abbas and Sharon. Sixty-eight people on both sides have been killed since then.

Abbas has been unable to persuade violent Palestinian groups to stop attacks on Israelis, a key demand of the peace plan.

In the attack Friday, Tzvi Goldstein, 47, was hit by gunfire as he drove with his wife and parents near the West Bank town of Ramallah (search). Goldstein, who held both Israeli and U.S. citizenship and moved to Israel 15 years ago, was heading to a celebration in Jerusalem a day after his son's wedding.

He managed to continue driving for six miles after the attack before his car overturned, according to Israeli rescue services. He was dead by the time rescue workers arrived.

His parents, Gene and Lorraine Goldstein, both 73, of Plainview, N.Y., were in serious condition with bullet wounds, according to Yael Bossem-Levy, a spokeswoman at Jerusalem's Hadassah Hospital. His wife, Michal, who also holds U.S. and Israeli citizenship, was not shot but was injured when the car overturned, Bossem-Levy said.

Gene and Lorraine Goldstein were in Israel for their grandson's wedding and were staying with their son at his home in the West Bank settlement of Eli, said David Bedein, a prominent settler in the West Bank.

At the Goldstein's home in Plainview, an unidentified woman handed out a brief statement that said the Goldsteins are "in the hospital, and from what we understand from family members in Israel they are receiving the medical attention that is required."

A Hamas-linked Web site claimed responsibility for the shooting on behalf of the militant group.

Troops were searching the area for the gunmen, the army said.

Powell condemned the attack, offered condolences to the victim's family and reiterated U.S. support for a crackdown on Palestinian terror groups.

"All around us are extremists who want to block our path," he said after meeting with Abbas. "We must not allow terrorists to win."

In the Gaza Strip clash, a 25-year-old Palestinian militant was killed by the Israeli army Friday night, Palestinian hospital officials said.

The man was among militants on their way to attack the settlement of Neve Dekalim when the army fired on the group, Palestinians said. The Israeli military had no immediate comment.

Earlier Friday, a booby-trapped bicycle left against a concrete road barrier exploded harmlessly at an Israeli military checkpoint in the Gaza Strip, the military said. A short while later soldiers found a second bicycle rigged with explosives and detonated it safely.

In a meeting Thursday night, mediated by American envoy John Wolf, Palestinian security chief Mohammed Dahlan told an Israeli defense official, Maj. Gen. Amos Gilad, that brokering a cease-fire was impossible as long as Israel continues its raids against militants, a Palestinian security source said on condition of anonymity.

Israel demands the Palestinians also disarm and shut down the militant groups. In the meantime there will be no let up in what Israel terms targeted killings of "ticking bombs." Those targets, as loosely defined by Israel, include those strapped with explosives or carrying rifles on their way to attack, as well as planners, bombmakers and those giving orders.

Sharon aide Raanan Gissin said Friday that such measures were necessary and would only stop when Palestinians shut down militant groups and arrest terrorists, who have killed hundreds of Israelis.

Israel has offered to withdraw its troops from parts of Gaza and allow the Palestinians to assume security control there, but the Palestinians say their forces, badly damaged by the Israeli military during the violence, are not yet prepared to take charge.

Opening a main north-south road in the Gaza Strip to the free-flow of Palestinian traffic was another sticking point in the talks. Even after withdrawing from Gaza, the Israelis want to keep army checkpoints along the highway, rejecting a request to ease restrictions that have prevented movement and ruined livelihoods, the Palestinian security source said.