JERUSALEM — Israel's defense minister said yesterday he will send large forces into Palestinian neighborhoods if Israeli troops and settlers come under fire during the withdrawal from the Gaza Strip during the summer.

The military faces twin threats during the pullout, from extremist settlers and from Palestinian militants.

Settlers want to stop the evacuation of all 21 settlements from Gaza and four from the West Bank, while militants want to show they are driving the Israelis out by force.

Palestinian attacks during the Gaza withdrawal "would require us to go into Palestinian Authority territory with very, very large forces to those places which overlook the areas to be evacuated," Defense Minister Shaul Mofaz said.

National-security adviser Giora Eiland said yesterday that Israel might leave houses in Gaza settlements intact, reversing earlier assertions they would be torn down to spare settlers from the sight of Palestinians taking them over.

Eiland said that would increase the cost of the withdrawal by about $18.4 million. "We advise against destroying the homes," he told Israel Radio.

Agriculture Minister Shalom Simhon warned that demolishing the homes would require Israel to deal with tons of debris, some of it containing asbestos, a carcinogen.

Simhon said TV images of Palestinians dancing on the red-tiled rooftops of the settler homes after the withdrawal are not as big a concern as "the damage we will cause to the aquifers, to the health of the public."

Palestinians have said they would replace the single-family dwellings with high-rise apartment buildings.

Speaking in London yesterday, U.S. Secretary of State Condoleezza Rice demanded the Palestinian Authority directly take on militants such as those behind the suicide bombing in Tel Aviv that killed four Israelis last week.

While the Bush administration has long called on Palestinian leaders to take on militant groups as prescribed under the U.S.-backed peace plan, it has not so publicly demanded this of Palestinian President Mahmoud Abbas since his Jan. 9 election.

"Ultimately people are going to have to be willing to fight terrorism, one way or another, and ultimately there is going to have to be both a desire and a capability to bring an end to the terrorist infrastructure that feeds attacks," Rice said.