JERUSALEM, Israel – The leaders of Jewish settlements in the Gaza Strip and West Bank urged their followers yesterday to resist a government plan to withdraw from parts of the occupied territories, edging closer to open revolt against Prime Minister Sharon’s plan to pull out next summer.

While the leaders said they remained opposed to violence, their call for civil disobedience – even at the risk of going to jail – marked the first time they have advocated breaking the law.

The announcement came on the eve of a visit by Prime Minister Blair, who will push to restart Middle East peace talks following the death of Yasser Arafat. In a setback for Mr. Blair, Israel bowed out of a proposed Middle East conference in Britain, after earlier indicating it would attend.

Since Mr. Sharon announced his withdrawal plan early this year, the settler movement has tried to defeat it through political lobbying and an aggressive advertising campaign.

Last summer, their political allies quit Mr. Sharon’s ruling coalition in an attempt to undermine him, leaving the prime minister with a minority government. Settlers also enjoy strong support among many legislators in Mr. Sharon’s Likud Party.

But Mr. Sharon has managed to outmaneuver them, turning to the moderate opposition for support as his hardline coalition crumbled. That strategy appeared headed for success yesterday, when Parliament endorsed a reform bill that is expected to clear the way for the moderate Labor Party to join the government. A coalition with Labor would restore Mr. Sharon’s majority, guaranteeing strong Cabinet support for the Gaza withdrawal.

With their political options dwindling, leaders of the Yesha Settlers Council, a group representing settlers in Gaza and the West Bank, endorsed a call by a prominent leader, Pinchas Wallerstein, to resist the withdrawal.

In a message distributed to settlers and repeated in a radio interview, Mr. Wallerstein said he is ready to go to prison for his beliefs.

“The Yesha council stands behind Pinchas Wallerstein,” council head Bentsi Lieberman said later at a news conference. “The proposal to expel Jews from their homes is an immoral decision and a breach of human rights.” Yesha is a Hebrew acronym for Judea, Samaria, and Gaza, the biblical names of the territories.

Mr. Lieberman said the settlers oppose violence and would not use force against soldiers involved in the evacuation.

Outside the news conference, settler activists and opponents squared off. The opposition activists held torches in the air, along with signs saying “Peace Yes, Occupation No.” The settlers danced around their opponents, holding signs saying “We’re all Pinchas.”

Mr. Sharon called Mr. Wallerstein’s statement “harsh.” Mr. Sharon, who for decades was the leading patron of the settlers, said he understands their pain, but that they must not break the law.

Ran Cohen, an opposition lawmaker with the dovish Yahad Party, accused Mr. Wallerstein of making “a declaration of war,” claiming that there are several dozen extremist settlers who are ready to resort to violence.