At least seven Israelis are dead after Palestinian gunmen detonated a roadside bomb near a bus in the West Bank and then opened fire as victims fled. Twenty-five people are reported wounded in the attack.

The Palestinian militants detonated the explosives near a bus at the entrance to the Jewish settlement of Emmanuel, southwest of Nablus in the West Bank.

Eyewitnesses said that after the first blast, there were several smaller explosions.

Three Palestinian gunmen, wearing Israel army uniforms, were waiting in ambush and began shooting passengers as they tried to exit the damaged vehicle. The gunfire continued for several minutes before the assailants fled in the direction of Nablus.

Israeli helicopter gunships were dispatched to the area in an effort to track down the gunmen.

Some of the victims are reported to have been in a car that had been traveling ahead of the bus at the time of the attack.

It was the deadliest attack against civilians since June 19, when Israel launched a military offensive against the West Bank in an effort to halt Palestinian terrorism. Israel has blamed the Palestinian Authority for the killings.

Raanan Gissin, a spokesman for Israeli Prime Minister Ariel Sharon, said the killings prove that the Palestinian Authority is determined to pursue a policy of terrorism in pursuit of its political goals.

"After a period of relative calm in the last few weeks, as the result of our Operation Determined Path, in which we were in and around the major cities in the West Bank, we were able to stop most of the terrorist activity. Today one of those attacks slipped through. An attack against Bus-189 enroute to Emmanuel, a roadside explosive and a well-planned ambush against these innocent civilians, who were passing by, who were traveling in this bus," Mr. Gissin said.

The Al-Aqsa Martyrs' Brigades of Palestinian leader Yasser Arafat's Fatah faction, the Democratic Front for the Liberation of Palestine, and the militant group Hamas each claimed responsibility for the attack.