A suspected Palestinian suicide bomber attacked Israeli soldiers in the Gaza Strip Thursday, in a car laden with explosives. The attack came hours after an Israeli helicopter fired at a car in Gaza, killing a known Palestinian militant. A car bomb exploded late Thursday, close to Israeli soldiers in the Kfar Darom area of the southern Gaza Strip.

As the blast went off, killing the driver, other Palestinians lying in ambush opened fire on the soldiers.

The Israeli forces returned fire, and began searching the area for the assailants.

The incident followed an Israeli military operation earlier in the day, in which an attack helicopter fired missiles at a car in Gaza City.

The occupant of the vehicle, Iyad El-Bek, a senior military commander of Hamas, was killed.

A spokesman for Hamas, the Islamic Resistance Movement, warned that the organization would launch a new wave of attacks to avenge his death.

The latest violence came just two days before the expected arrival of Secretary of State Colin Powell, who is urging Israel and the Palestinians to adopt a new international peace plan to end their conflict.

Known as the road map to peace, the plan is supported by the United States, Russia, the European Union and the United Nations.

The document calls for an end to the Israeli-Palestinian conflict and the establishment of an independent Palestinian state by 2005.

The Palestinian prime minister, Mahmoud Abbas, said Thursday that the plan will only succeed if the United States puts pressure on Israel to implement it.

He is expected to meet Israeli Prime Minister Ariel Sharon next week, shortly after Mr. Powell's visit.