The rash of violence that has overtaken the Mideast in recent days has caused Hamas (search) -- the target of four Israeli missile strikes -- to order an all-out assault on Israel, while Prime Minister Ariel Sharon (searchvowed to press on in their "war on terror" against the Islamic militant group.

Israeli helicopters on Thursday launched an attack which killed a Hamas commander and six others, including his wife and 2-year-old daughter in Gaza (search). Hours later, Israeli soldiers in the West Bank town of Jenin hunted and killed two Islamic Jihad activists.

Between those two operations, Palestinians shot and killed an Israeli motorist in the West Bank. Early Friday, Israeli tanks entered the Tulkarem refugee camp in the West Bank, residents said, blocking roads.

Israelis spent Thursday burying victims of a Hamas homicide bombing (searchon a bus in Jerusalem the day before. Seventeen passengers and bystanders were killed.

Responding to the Israeli air strikes in Gaza that killed 20 Palestinians, including several senior Hamas commanders, Hamas issued one of its darkest threats yet, ordering "all military cells to act immediately and act like an earthquake to blow up the Zionist entity and tear it to pieces."

The group said foreigners should leave for their safety. Hamas has generally acted on its threats.

Sharon, in turn, said he would fight militants "to the bitter end," regardless of the road map.

The United States on Thursday called a meeting of its fellow Mideast mediators to try to salvage their "road map" peace plan, which is in danger of disintegrating.

With the "road map" plan leading nowhere because of the surging violence, the U.S. State Department announced that Secretary of State Colin Powell would meet in Jordan next week with leaders of U.S. partners in the "Quartet" of mediators sponsoring the peace plan -- The European Union, United Nations and Russia.

Powell called on Abbas to work harder to rein in militants. "We want him to use that limited capability as effectively as he can," Powell told The Associated Press in an interview after talking to Sharon and Abbas on the telephone.

Addressing his own Cabinet, he ridiculed Palestinian Prime Minister Mahmoud Abbas' ministers, calling them "crybabies" for saying that they can't crack down on Hamas. "If I need to choose between the war on terror and supporting Abu Mazen, I will chose the first option," Sharon said, referring to Abbas by his nickname.

Abbas, noting that Israeli strikes have decimated his security services, prefers to persuade the Islamic militants to stop attacks against Israel, but Hamas pulled out of truce talks last Friday.

The Israeli air strikes against Hamas leaders infuriated the militant group and pushed away any thoughts of a cease-fire, weakening Abbas' already shaky political position.

In Cairo, Arab League Secretary-General Amr Moussa said U.S. observers must be sent soon. "We all have to stop the violence and the bloodshed or at least freeze the situation for sometime until things are cooled off ," Moussa told reporters after meeting PLO official Farouk Kaddoumi.

Assistant Secretary of State John Wolf is to arrive in the coming days with a team of American observers, part of the road map plan.

In Thursday's strike, Israeli helicopter gunships fired missiles at a car carrying Yasser Taha and Ibrahim Abu Srour, two Hamas fugitives from the group's military wing.

In all, seven people were killed, including Taha's wife, Fatima, 25, and their 2-year-old daughter, Asnan, doctors said. A baby bottle and baby shoes were pulled from the burning car. Twenty-nine people were hurt in the strike.

Israel army spokeswoman Maj. Sharon Feingold expressed regret at the civilian casualties and pledged an investigation. "A result of a mistake, family members were also killed," she said. "They were not targets."

The car was targeted in Gaza City's Sheik Radwan neighborhood, just as mourners were leaving a nearby cemetery, where 11 dead from two previous air strikes were buried. Witnesses said one missile struck as bystanders surrounded Taha's car.

Thursday's funeral procession was attended by about 35,000, who chanted: "Abu Mazen, listen closely. There is nothing except jihad (holy war)."

After nightfall Thursday, Israeli forces killed two Islamic Jihad activists who drew guns on soldiers who came to arrest them in the West Bank town of Jenin, the military said. Witnesses said special forces entered the town and opened fire on the two.

In the same area, Palestinian gunmen shot and killed an Israeli motorist as he left the village of Yabed after shopping. The Israeli was violating an Israeli ban on its civilians from entering Palestinian areas.

The Associated Press contributed to this report.