HAVAT GILAD, West Bank - Israeli Prime Minister Benjamin Netanyahu yesterday rejected President Obama's demand for a freeze on West Bank Jewish settlement construction, but his government's move to dismantle some squatter camps set off a rampage by Jewish settlers against Palestinians.

It was a violent reminder that Netanyahu is caught between his own hard-line supporters and Israel's vital relationship with Washington. So far, Netanyahu has appeared sympathetic to the settlers, but protests over his West Bank policy spread as far as Jerusalem.

Yesterday, Netanyahu briefed the Israeli parliament's Foreign Affairs and Defense Committee about his recent meeting with Obama. The president and Secretary of State Hillary Rodham Clinton have demanded that Israel halt all settlement construction, including expansion to accommodate what Israel calls "natural growth" of settlements.

Netanyahu said Israel cannot "freeze life" in settlements, according to a participant. Netanyahu was quoted as saying that "there are reasonable requests and unreasonable requests."

At the same time, in an apparent gesture to Obama, Netanyahu's government has begun dismantling small settler outposts built without formal government authorization. That has triggered settler violence.

Settlers have vowed to retaliate with attacks on Palestinians after removal of even the tiniest enclave.

"We will do everything we can to oppose this," said settler Yehuda Shimon at the Havat Gilad outpost in the northern West Bank.

Yesterday's settler violence started near the settlement of Yizhar, police spokesman Micky Rosenfeld said. About 100 settlers blocked a road. Six were arrested.

Before dawn, near the Kedumim settlement, stone-throwing settlers ambushed a minivan carrying Palestinian laborers to Israel, the workers said. Six of the 15 Palestinians on board were hurt. Police said settlers threw rocks and burned tires and then fled. Police said no arrests were made.

A few hours later, settlers torched a wooded hilltop near Nablus and set trees and Palestinian agricultural land on fire near the village of Hawara, residents said.

Toward nightfall, about 20 Jewish young people briefly blocked the highway into Jerusalem, burning tires and a trash bin, causing a huge rush-hour traffic jam. Police dragged the struggling youths away, arresting four.

One of the protesters, Menachem Novick, 28, said the goal was to press Netanyahu and his party to keep their campaign pledge to expand the settlements. "We want to give them a push to do what they were elected to do," he said.

On another touchy diplomatic front, U.N. investigators yesterday began looking into possible war crimes during Israel's three-week offensive in December and January against Gaza's Hamas rulers, even though they failed to secure a promise of cooperation from Israel.

Israeli officials have insisted the investigation, led by veteran war-crimes prosecutor Richard Goldstone, would not be objective.