Prime Minister Ariel Sharon (search) on Monday named five large West Bank settlement blocs he wants to keep as part of his final peace plan — then flew to Washington win President Bush's support for the "disengagement" effort.

Sharon appeared to confirm Palestinian fears that Israel plans to withdraw from the Gaza Strip (search) and four smaller West Bank settlements in order to strengthen its hold over other parts of the West Bank.

Sharon's wants to "strengthen and develop" the five blocs, putting his plan at odds with the U.S.-backed "road map" peace plan which calls for an Israeli settlement freeze ahead of negotiations on a final peace deal.

Hours after speaking, Sharon left for Washington where he will ask Bush to back his plan of unilateral disengagement from the Palestinians.

Bush said Monday that he would welcome a Gaza withdrawal as a "positive development," but it appears unlikely the U.S. president will meet Israel's request — a U.S. declaration that Israel can keep part of the West Bank in a final peace deal with the Palestinians.

Such a declaration would undermine the "road map," which envisions a Palestinian state by next year, with the borders to be negotiated by both sides.

According to senior Israeli government officials, who spoke on condition of anonymity, Sharon and Bush will exchange letters at their Wednesday meeting, outlining commitments to the withdrawal plan and to the road map.

Sharon's letter will say that Israel will pull out of all 21 Gaza Strip settlements and four isolated West Bank enclaves, the officials said. In exchange, Bush will say Israel has a right to "pursue terrorists," including in areas from which it has pulled out, the officials said.

Sharon visited Maaleh Adumim (search), the West Bank's largest settlement with 30,000 residents. Sharon was attending celebrations marking the end of the weeklong Jewish holiday of Passover.

Sharon told about 500 people gathered in a Bedouin-style tent that in giving up Gaza and parts of the West Bank, Israel would gain security and be able to keep large settlement blocs.

"Only an Israeli initiative will assure the future of the large settlement blocs and the security zones, like a strong Maaleh Adumim, a strong Ariel, a strong Givat Zeev, a strong Etzion bloc — places that will remain under Israeli control, will continue to be strengthened and developed, and I also add a strong Hebron and Kiryat Arba," he said.

It marked the first time Sharon detailed which settlements he wants to keep in a final peace deal. Asked what would happen to the other West Bank settlements — there are 140 altogether — Sharon aide Raanan Gissin said their fate would be determined in peace talks.

Givat Zeev, Maaleh Adumim and the Etzion bloc are north, east and south of Jerusalem, respectively. Ariel, Kiryat Arba and the tiny settler enclaves in Hebron are deep in the West Bank, and their annexation by Israel would make it difficult to create a Palestinian state with contiguous territory.

Palestinian Cabinet minister Saeb Erekat said that "settlements in the West Bank are just as illegal as those in Gaza."

If Israel tries to annex part of the West Bank, "we will not get to peace and not to security," Erekat said.

Sharon portrayed his disengagement plan as a "mortal blow" for the Palestinians, and said he hoped it would spur them into action, including restraining militants. "When they see it as the end of their dreams, then perhaps they will take the necessary steps," he said.

The prime minister is trying to persuade his hardline Likud Party to approve the disengagement plan in an April 29 referendum.

However, approval is not assured, with Sharon given only a slight edge in the polls. Leading Likud figures oppose a Gaza withdrawal, and have begun campaigning against Sharon.

If Sharon wins the vote, he plans to have it approved by the Cabinet and then parliament just days later. If he loses, he could come under growing pressure to resign.

In Washington, Sharon aides held an unscheduled meeting Monday with administration officials at the White House to try to close gaps between what Israel wants and the United States is willing to give, an Israeli official said on condition of anonymity.

The Palestinian prime minister, Ahmed Qureia (search), said Monday that the Palestinians would not recognize any U.S. guarantees to Israel that pre-empt final peace talks.

The U.S. administration wants to show progress to its Arab allies in the face of mounting criticism of its handling of the crisis in Iraq.

On Monday, Bush met with Egyptian President Hosni Mubarak (search) at his ranch in Crawford, Texas. Later this month, Jordan's King Abdullah is to meet with Bush, and Palestinian Foreign Minister Nabil Shaath is to hold talks with senior U.S. officials.

In Gaza, Palestinian factions have been competing for influence ahead of the expected Gaza pullout. Palestinian security chief Rashid Abu Shbak announced Monday that activists from Palestinian leader Yasser Arafat's Fatah faction in Gaza would hold internal elections in the next few days.

Abu Shbak also said power-sharing talks with Hamas are continuing.

Also in Gaza, the Israeli military shot dead two militants as they tried to attack an army base near the Israeli settlement of Netzarim.

Hamas, Islamic Jihad and the Al-Aqsa Martyrs' Brigades (search) claimed joint responsibility for the attack. Al-Aqsa is a militant group loosely linked to Fatah.