Updated

In a last-minute bid to shore up crashing support for his Gaza withdrawal plan, Israeli Prime Minister Ariel Sharon gave a series of interviews broadcast Thursday painting an upcoming referendum on the plan as a vote of confidence in him. He stopped short of threatening to resign, however.

Polls have shown dwindling support for the plan in recent weeks, and new surveys published Thursday indicated for the first time the proposal would fail in Sunday's referendum of the 200,000 members of Sharon's Likud Party (search).

In Gaza City, tens of thousands of Palestinians demonstrated in support of Palestinian leader Yasser Arafat and against Israeli threats to harm him.

Also in Gaza, a remote-controlled bomb went off in the house of the Gaza police chief, Ghazi Jabali (search), destroying the ground floor. Jabali had left a few minutes earlier, and no one was hurt. Residents found a 25-yard wire leading from the scene, attached to a switch.

The blast apparently stemmed from violent, internal Palestinian rivalries. A February shootout at Jabali's Gaza office with backers of rival Gaza strongman Mohammed Dahlan (search) killed one police officer and wounded 10 others.

Some of the internal Palestinian violence has been attributed to a jockeying for power among different groups ahead of Sharon's proposed pullout from the Gaza Strip.

Two polls published in Israeli newspapers Thursday indicated a significant shift of opinion among Likud voters against the "disengagement plan," which would also include the evacuation of four small West Bank settlements.

A survey in the Maariv daily showed 45 percent of Likud members opposountry to whip up support.

Sharon met with advisers Thursday and newspapers reported that many of his aides have already started blaming each other for what they view as a coming debacle.

In interviews with radio stations and newspapers that were broadcast and published Thursday, Sharon called his opponents "the extreme right wing," said a "no" vote would be a victory for Palestinian militants and warned Likud voters that the plan's defeat would have dire consequences.

He suggested it could force the party out of power, but stopped short of saying he would resign in case of defeat. "You can't be for me, but be against my plan," Sharon told Israel Radio.

"Whoever wants me understands that only in this way can I fulfill my promise to bring peace and security. Whoever believes in me must vote for the disengagement plan ... Whoever supports me must vote for the plan," Sharon said.

When asked what he would do if he lost, Sharon responded: "I don't even want to think of that situation."

A pro-Sharon rally led by Vice Premier Ehud Olmert was interrupted Wednesday by residents of the Jewish settlement of Homesh in the West Bank, one of those marked for evacuation. At the gathering in a Haifa suburb, a settler shouted: "We will not be quiet. They are massacring us and murdering us."

Olmert was scheduled to visit a Gaza settlement Wednesday, but was told by residents he was not welcome.

Opponents called tens of thousands of Likud members Wednesday to play them a recording against the plan by the mayor of the southern town of Sderot, Eli Moyal, Maariv reported.

Moyal believes the withdrawal would leave his town exposed to rocket attacks by Palestinian militants in the nearby Gaza Strip.

Sharon's plan was bolstered by President Bush's endorsement two weeks ago and his backing for Sharon's position that Israel should not have to give the Palestinians all of the West Bank or let Palestinian refugees return to Israel in a peace deal.

But many in Sharon's traditionally pro-settler party remain wary of pulling down Jewish settlements.

Sharon had originally promised to honor the Likud referendum, but backed down last week, with advisers saying he will present his plan to the Cabinet and parliament regardless of the vote's results.

Earlier this month, Sharon said he was no longer bound by a promise to the United States not to assassinate Arafat.

In Gaza City on Thursday, thousands of school children, university students, public workers, Palestinian security forces and members of the other militant factions marched with posters of Arafat and signs warning Israel not to harm him.

"Killing him or harming him means that the Palestinians will delete the word peace from their dictionary," said a gunman from Arafat's Fatah party who identified himself as Abu Nasser.