Gunmen shot and killed two Israeli security guards Saturday at a construction site for the disputed barrier that Israel is erecting along its frontier with the West Bank (search).

The incident occurred hours after Israeli troops shot dead two Palestinians, including a 10-year-old boy, after a stone-throwing clash in the West Bank escalated into a gun battle with militants.

All four killings underscored the daily violence that has characterized the three-year-old conflict, which has killed more than 2,500 Palestinians and almost 900 Israelis. The new bloodshed came as efforts were underway to craft a cease-fire deal and restart frozen peace talks.

The two Israeli security guards were sitting in their car, keeping watch over heavy equipment that was being used to prepare the way for a Jerusalem-area section of the barrier.

They were shot at close range after dark on Saturday, and their weapons were stolen, Jerusalem Police Chief Micky Levy said. Three other security guards arrived and fired shots as the assailants fled.

The Jenin Martyrs Brigade (search), a militant group believed to be linked to Palestinian leader Yasser Arafat's Fatah (search) faction, claimed responsibility for the shooting in a statement faxed to news media.

Israeli Foreign Ministry spokesman Daniel Taub criticized the Palestinian leadership for not doing more to stop attacks and dismantle violent extremist groups.

"This is another tragic loss of life," Taub said.

Palestinians have vehemently opposed Israel's construction of the fence, which in places cuts into the West Bank, cutting off Palestinian land. Israel says the barrier is needed to prevent suicide bombers from entering its territory.

In the West Bank Saturday, about 35 Israeli peace activists traveled to the Palestinian village of Einabus with olive tree saplings to show their sympathy over the cutting of 250 olive trees there last month, apparently by Jewish settlers in the area.

Village resident Fawzi Hussein said the Israeli activists wanted to plant six olive saplings next to the grove where his trees were cut but the army would not let anyone into the area, calling it a closed military zone, in an apparent effort to prevent scuffles with the settlers.

"I said, 'This is my land' and the army said, 'You have nothing to do here,"' Hussein said. The saplings brought by the group were left with school children.

Israeli police have said they are investigating the cutting of the trees but have not yet made any arrests. The fall olive harvest accounts for a crucial portion of the local Palestinian economy, especially since many are without work because of the conflict.

In fighting Saturday, Israeli troops fired on a crowd of youths hurling stones in the West Bank town of Jenin, killing 10-year-old Ibrahim Jalamneh, witnesses said. The military said some in the crowd threw gasoline bombs and the troops opened fire after being fired on by a gunman in the crowd.

The clash widened into a gunbattle with members of a militant group.

An army spokesman said the boy's death was under investigation. Palestinian doctors said he was hit by a single bullet in the chest. A short time later, a group of young boys knelt around the child's body at a mosque. His face was framed with a scarf, his eyes and mouth open slightly.

Earlier, in the Gaza Strip, Israeli soldiers shot and killed a Palestinian from the violent Islamic Hamas group as he was apparently trying to lay a bomb to target military patrols near the fence with Israel. The military said troops found a Kalashnikov assault rifle and a 44-pound bomb near the man's body.

In another development, a Palestinian official reacted with skepticism to an Israeli TV report that Prime Minister Ariel Sharon might begin next summer to dismantle several Jewish settlements in the West Bank and Gaza Strip — territories the Palestinians want for a future state.

Israel's Channel Two TV reported the story Friday but did not cite any source for the information.

Palestinian Cabinet Minister Saeb Erekat said he hoped the report of settlement removal was not simply a "public relations stunt."

"We need genuine moves toward peace," he said Saturday, calling for the implementation of the U.S.-backed "road map" peace plan, which aims to stop the fighting and create a Palestinian state by 2005.

The settlement report followed a speech Sharon made Thursday, in which he said he was considering going ahead with some unilateral steps toward the Palestinians.

Sharon did not elaborate, and Israeli media have been speculating that he is planning soon to announce a program of steps that might include easing travel restrictions on Palestinians or changing the way the military operates in the West Bank and Gaza Strip.