By Allyn Fisher-Ilan

JERUSALEM (Reuters) - Armed with fresh White House endorsement for his Gaza pullout plan, Israeli leader Ariel Sharon vowed on Wednesday to push it past rebellious ministers and evacuate all settlements in the territory by 2005.

Sharon is battling a political crisis that threatens to bring down his government. He needs to win cabinet approval on Sunday for an initiative, supported by most Israelis, to give up the territory captured in the 1967 Middle East war.

He faces off against rebels led by influential rival and Finance Minister Benjamin Netanyahu, who oppose a plan rejected by members of the ruling Likud party as a victory for "Palestinian terror."

"The plan will pass on Sunday," Sharon told reporters after a parliamentary security committee session. He told the meeting the 21 settlements in the Gaza Strip and four out of about 120 in the West Bank would be evacuated by the end of 2005.

The former general, nicknamed "The Bulldozer" for his hard-nosed tactics, failed to muster enough votes last Sunday and the vote was postponed.

Strengthening Sharon's hand, the United States said President Bush would only back the full Gaza pullout proposed by Sharon and not a watered-down version suggested by some ministers as a possible compromise.

"It is that plan that he (Bush) supports now and no other," an embassy spokesman said in Tel Aviv, reinforcing Sharon's warning that unprecedented U.S. assurances on keeping West Bank land, which drew international condemnation, could be at stake if the plan is blocked.

Less likely to win favor for Sharon was a fresh endorsement for a withdrawal from the Hamas Islamic militant group, which has sworn to destroy the Jewish state. Israeli opponents fear a Hamas takeover if troops leave Gaza.

While Palestinians would welcome a pullout from any of the land they seek for a state, they suspect Sharon's plan is just a ruse to strengthen Israel's hold on chunks of the West Bank.

Insiders said despite Sharon's apparent confidence on Wednesday, there was no guarantee that he had won over enough cabinet members to assure victory on Sunday.

If he thinks he will not get a majority, then Sharon has the option of either sacking ministers opposed to the plan or bringing in new ones who would back it.

Whichever way the vote goes, it could trigger the collapse of the government, since far-right coalition allies have threatened to walk out if the plan is passed.

Possibly raising the stakes ahead of the vote, some officials dropped hints fresh elections could be held within the next few months, but a confidant to Sharon said such an option was not being considered seriously.

"It is all about psychological pressure," he said. (Additional reporting by Megan Goldin)

Reuters