NEVE DEKALIM, Gaza Strip - Thousands of Israelis poured into the Gaza Strip's main Jewish settlement bloc today to protest this summer's planned withdrawal, show support for the settlers and bid farewell to the area Israel occupied for 38 years.

Gaza settler leaders said they expect at least 100,000 people, which would make it one of the largest demonstrations since Prime Minister Ariel Sharon announced the pullout plan last year. Turnout was expected to be bolstered by warm weather and the Passover holiday, when schools are closed and many people are on vacation.

Some settler leaders have expressed hope that the protesters will stay in Gaza to resist the withdrawal. However, Avner Shimon, mayor of the Gaza settlements, said he expected the visitors to leave after Passover.

"People are coming to enjoy themselves, see the place and hug us and to tell us they are with us. I estimate that nobody will remain when it is over," he told Israel Army Radio.

Palestinian militants fired a mortar shell into a Jewish settlement in the Gaza Strip during the march, injuring a soldier, the military said. The mortar shell was fired despite pledges by Palestinian militants to observe a cease-fire with Israel.

Early today, the Israeli army closed the main crossing into the Gush Katif bloc of settlements to private cars, allowing only buses through. Army Radio said 1,500 buses were expected to reach Gush Katif.

Organizers were selling orange flags and T-shirts, symbols of opposition to the withdrawal.

A procession through Gaza's seaside settlement began at midmorning, and a steady stream of people marched through the area. Many carried orange balloons and wore shirts and hats saying "a Jew doesn't expel a Jew."

Neve Dekalim resident Sylvia Mazuz said the festive atmosphere was misleading.

"Our hearts are heavy," said Mazuz, 44, who has lived in the settlement for 14 years.

Mazuz, whose husband, four children and grandchildren all live in the settlement, said she has made no preparations for life after withdrawal and remains hopeful the government will cancel the plan.

"We are waiting for salvation from God," she said, adding that she would resist the evacuation order solely through peaceful means.

Under the plan, Israel will withdraw from all 21 Gaza settlements as well as four small settlements in the West Bank. About 9,000 Jewish settlers are slated to be evacuated from their homes.

Sharon said the withdrawal will improve Israel's security while enabling him to cement Israeli control over large blocs of settlements in the West Bank. Since Sharon announced the plan, settlers have held a number of large rallies in Tel Aviv and Jerusalem. Today's rally was expected to be the largest protest inside Gaza so far.

"We want to create a sense in the public that this move is illegitimate," said Chaniel Nahari, who came to the protest from his home in central Israel. "The government is caving in to terror and isn't achieving anything."