The groups' three gunmen were then killed by Israeli troops. Hours later, Palestinians killed another Israeli soldier in the West Bank town of Hebron.

A total of six Palestinian militants were killed in weekend violence, one of the bloodiest 24-hour periods in recent weeks.

The attacks strike a blow to Palestinian Prime Minister Mahmoud Abbas' efforts to negotiate a cease-fire with militant groups, his strategy for ending anti-Israeli attacks as called for by the U.S.-backed "road map" peace plan.

Israel quickly demanded the Palestinians crack down on the extremists, but Abbas insisted he could still persuade them to stop.

Just four days ago, U.S. President Bush launched the "road map" peace plan at a summit in Jordan with Abbas and Israeli Prime Minister Ariel Sharon in an atmosphere of hope, with statements renouncing violence and calling for reconciliation.

Previous peace plans have drowned in floods of violence, and Secretary Colin Powell found it necessary Sunday to appeal to the two sides not to let it happen again.

"What we have to do now is to make sure we don't allow this tragic, terrible incident to derail the momentum of the road map," Powell said on "Fox News Sunday," referring to the Gaza attack.

The rare joint operation by Hamas, Islamic Jihad and the Al Aqsa Martyrs' Brigades was intended to send a message to Abbas that Palestinians will continue to fight Israel and will not "surrender to the pressure exerted by Israel and the United States of America," said Abdel Aziz Rantisi, a Hamas leader.

"We are unified in the trenches of resistance," he said.

The violence created a quandary for Abbas, who if he is unable to bring a cease-fire, may have to decide between launching a violent crackdown on those groups or abandoning the road map, which calls for an end to 32 months of fighting and envisions the creation of a Palestinian state by 2005.

The attack also put Sharon in a difficult position, forcing him to decide whether to retaliate - likely causing further damage to the peace efforts - or hold back and wait for Abbas to respond and suffer political criticism from within his hardline government.

Sharon's first test was a hostile convention of his own Likud Party in Jerusalem. Sharon was greeted with boos, unusual for a serving premier among his own followers, reflecting the high level of opposition to the road map and Sharon's conditional acceptance of it among Israeli hard-liners

The boos continued throughout Sharon's address to the delegates, in which he did not refer to Sunday's attacks, but insisted anti-Israeli violence must end before peace moves are made.

"Victory over terrorism is at hand," he said but insisted that attacks against Israelis "We will not give anything as long as the terror, violence and incitement continues."

"But we will be prepared to make painful concessions for real peace and security," he added.

Three militants, one each from Hamas, Al Aqsa and Islamic Jihad, disguised as Israeli soldiers and armed with assault rifles and grenades, attacked an army post near the Erez crossing into Israel just after dawn Sunday. The post guards an Israeli-run industrial zone at the northern end of the Gaza Strip.

Maj. Gen. Doron Almog, head of the army's southern command, said the attackers arrived by surprise at the northern edge of the post, killed three soldiers at close range and a fourth soldier inside the base.

Four other soldiers were wounded, the army said.

"This joint operation was committed to confirm our people's united choice of holy war and resistance until the end of occupation over our land and holy places," the militant leaflet said.

Late Saturday, Israeli troops in Gaza killed a Palestinian armed with an assault rifle and a pouch of grenades after he fired at them. The radical Democratic Front group said the man had been trying to attack a Jewish settlement.

Israeli Defense Minister Shaul Mofaz demanded Abbas begin cracking down on militants immediately.

"They must dismantle the terror organizations, and if they do not, we will not hesitate to take upon ourselves the task of fighting terrorism and ensuring the safety of our people," he said at the Likud Party meeting.

Abbas, however, said, "We will not allow anybody to drag us into a civil war." He has said his security services were decimated during months of fighting with Israel and incapable of taking on the militant groups.

Palestinian Foreign Minister Nabil Shaath accused Israel of provoking the attacks by continuing restrictions on Palestinians and killing two Hamas militants Thursday night near the West Bank city of Tulkarem in a gunfight.

Hamas, the deadliest of the groups, walked away from truce talks Friday, saying Abbas made too many concessions at the summit, where he condemned violence against Israelis and called for an end to the armed uprising.

On Saturday, Islamic Jihad and other radical factions declared they, too, would not stop bombings and shootings.

Citing security alerts, Israel reimposed a closure on the West Bank on Saturday night. After Sunday's shooting, Gaza crossings into Israel were also closed.

(China Daily June 9, 2003)