Kfar Maimon, Israel ? Israeli police backed by officers on horseback sealed off an encampment filled with thousands of Jewish settlers and their supporters Tuesday, trading punches and dragging off protesters in the biggest confrontation yet over Israel’s withdrawal from Gaza.

The government has vowed to stop protesters from marching to Gaza Strip settlements marked for evacuation in August, fearing that more Israeli hard-liners at the sites would further complicate the contentious pullout.

Demonstrators said they would stay in their makeshift protest camp in the farming community of Kfar Maimon and try to march again today – and the next day and the next – setting the stage for more confrontations.

“As long as this terrible decision stands (to withdraw from Gaza), there will be a constant presence to prevent this,” settler leader Pinchas Wallerstein told Army Radio.

The demonstration could shape up as the last major stand by opponents to Israel’s withdrawal from 21 Gaza settlements and four in the northern West Bank.

But protesters’ defiance and willingness to tangle with the authorities could also foreshadow difficulties awaiting the government as it tries to remove 9,000 residents from the condemned settlements.

The government said it was determined to push through with its “disengagement” plan, which Prime Minister Ariel Sharon unveiled a year and a half ago.

“Ariel Sharon is not scared of 20,000 or 50,000 marching settlers,” Vice Premier Ehud Olmert said.

Protesters had planned a three-day march beginning Monday in the southern Israeli town of Netivot and ending at the Kissufim crossing into Gaza, 15 miles away.

A Israeli supporter of the Jewish settlements movement walks past a line of border police officers at Kfar Maimon, southern Israel. Israeli police encircled an encampment of thousands of Gaza pullout opponents Tuesday, pushing back a surging crowd trying to march to the nearby Gaza Strip in a show of support for Jewish settlements marked for demolition next month.

The government outlawed the demonstration, stopped many protesters’ buses and sent 20,000 police and soldiers to block the march.

Thousands of the marchers, many of them teenagers and families with young children, stayed overnight in Kfar Maimon, 12 miles from Kissufim, and Defense Minister Shaul Mofaz said they would not be allowed any closer.

“My orders are unequivocal: not to let this march reach Gush Katif,” Mofaz told Israel TV, referring to the main cluster of Gaza settlements.

About 4 p.m., protesters surged toward the village gate, but police blocked their path. The sides traded punches, and two police officers were slightly injured. Police on horseback moved into the crowd; officers arrested 18 people.

“If they want to leave as individuals and go home, they are free to do so. But if they want to leave and march out as a group, we will stop them,” said police spokeswoman Sharon Brown.

The marchers had hoped to break through the newly fortified Kissufim crossing into Gaza on Wednesday and march toward the settlements – defying a government order last week blocking nonresidents from crossing into Gaza.

Thwarted, the demonstrators, numbering fewer than 10,000 by police count, turned Kfar Maimon into a protest village, holding sing-alongs and communal prayers. Portable toilets and drinking water were trucked in, and vendors sold sandwiches and sodas.