Israeli bulldozers knocked down houses in four Gaza (search) settlements Sunday, leveling once-thriving villages in hours as thousands of soldiers poured into four other communities in the final phase of removing holdout settlers from the coastal strip.

The troops were met by burning barricades, pleading settlers and a mock cemetery built "for anyone who expels Jews from their homes." Other settlers left in a dignified procession, quietly weeping.

By Sunday evening, the army said it had evacuated 20 of 21 Gaza settlements.

In the West Bank (search), extremists exchanged blows with soldiers and slashed tires of army jeeps near Sanur, an enclave to be dismantled later this week. Police said 10 officers suffered light injuries in skirmishes that gave a foretaste of violent confrontations expected when forced evacuations shift to the West Bank.

A senior U.S. envoy said during a meeting with Palestinian leader Mahmoud Abbas (search) that Israeli's pullout would boost the U.S.-backed "road map" peace plan that envisions Palestinian statehood.

"The United States views the Israeli disengagement from Gaza as an important opportunity to re-energize the 'road map,' to take further steps forward toward a better future for Israelis and Palestinians," U.S. Assistant Secretary of State David Welch said.

Palestinian negotiator Saeb Erekat said the two sides agreed that "Gaza will not be first and last." The Palestinians want to create a state comprising the Gaza Strip, all of the West Bank and east Jerusalem.

Clouds of cement dust loomed over the Gaza settlements of Nissanit, Dugit, Peat Sadeh and Ganei Tal in the first large-scale demolitions since the Israeli pullout began six days ago, adding an air of finality to the pullout by making it obvious the settlers can never go back.

Crews are demolishing the homes as part of an agreement with the Palestinian Authority, which wants to build apartment buildings at the former settlements to deal with a severe housing shortage among the 1.3 million Palestinians in the Gaza Strip.

Security officials said 50 bulldozers were operating in Gaza. A senior Defense Ministry official, Victor Bargil, said all 21 Gaza settlements would be razed within two weeks, about half the time previously predicted.

Excavators and huge D9 bulldozers plowed through the whitewashed walls of red-roofed homes, leaving mounds of rubble and abandoned belongings reminiscent of Israel's large-scale house demolitions in Palestinian communities during five years of fighting.

In Nissanit, cranes lifted prefabricated homes and loaded them on flatbed trucks, to be driven to Israel. Piles of rubble lined the main street. Houses were leveled in the settlement of Dugit.

In Jerusalem, Israel's Cabinet gave final approval to the evacuation of the last seven of 25 Gaza and West Bank settlements marked for dismantling.

At the start of the meeting, Prime Minister Ariel Sharon called acts of violent resistance to the pullout "hooliganism" and said Jewish settler leaders — once his friends and allies — were exploiting the suffering of their followers to push a political agenda.

The forcible removal of settlers from their Gaza communities began Wednesday, more than a year after Sharon concluded that Israel no longer could defend its 38-year occupation of the coastal strip. The evacuations have proceeded with relatively little violence.

The government is compensating settlers through a complex formula that takes into account such issues as home size, number of family members and amount of time residing in the settlement. Compensation usually amounts to $200,000-$300,000 per family.

Settlers who stayed in Gaza after the deadline could lose some of that compensation.

Katif, Atzmona and Slav — the remaining communities in the main settlement bloc, Gush Katif — were emptied Sunday, as was the northern Gaza settlement of Elei Sinai.

The last of the Gaza settlements, Netzarim, is to be evacuated Monday, with the entire Gaza evacuation compressed into just one week, far shorter than the three weeks security forces foresaw.

In Katif, an Israeli army bulldozer broke through the community's locked gates Sunday to clear a blazing fire of hay, tire and wooden planks so troops could move freely.

Longtime resident Haim Ben-Arieh walked over to the commander of the group that had come to evict his family, shook his hand and urged him to refuse to carry out the mission.

"I'm very sorry," said the soldier, who looked on the verge of tears.

He gave the family until after noontime prayers to leave their unpacked home.

Ben-Arieh then turned to clip his front hedge.

"I love this place and will take care of it until the bitter end," he said.

Earlier, an emotional memorial ceremony was held for Katif settler Tali Hatuel, 34, and her four children, ages 2-11, who were killed in May 2004 by Palestinian gunmen who ambushed them on a Gaza road.

Mourners surrounded five plastic chairs, each bearing a handwritten note with the name of the dead and the orange ribbon of pullout opponents tied to the back. A memorial candle was placed on each chair, and crying women lit the candles as men swayed back and forth in prayer. Hatuel's sobbing husband, David, was comforted by family and friends.

In Atzmona, outside the home of the Harush family, stood a mock cemetery with cardboard tombstones bearing the names of the Jews' foes across the ages — Pharoah, Titus, Haman, Hitler and Arafat.

An empty grave marked by a blank tombstone "was dug for anyone who expels Jews from their homes," explained 14-year-old Yehoyada, from the West Bank settlement of Efrat, who refused to give his family name.

Soldiers entering Slav encountered no resistance from the few remaining families. Most left earlier to avoid being evicted.

Security forces also entered the northern Gaza settlement of Elei Sinai, where residents planned to leave on foot and walk to a gathering place in nearby Israel. Troops were going house to house there telling people to leave.

Security officials expect violent resistance this week during the forcible evacuation of two northern West Bank communities, Sanur and Homesh, where some 2,000 anti-pullout opponents camped out preparing for a fight.

Dozens of Jewish settlers traded blows Sunday with Israeli soldiers outside Sanur. Witnesses said settlers slashed the tires of an army jeep and attacked a TV cameraman.

"We expect some harsh resistance there," an army spokeswoman, Maj. Sharon Feingold, told The Associated Press. "We know that some of them are armed, and we're still in dialogue with them."