Israel has not decided the form of its much-discussed withdrawal from Gaza, according to a senior Israeli source.
Israel is concerned about weapons being smuggled into Gaza
The source said that a complete pullout is the most likely scenario, but other options are still being considered.
They include a pullout of settlers only from the south part of the Gaza Strip; maintaining control of the Gaza-Egypt border; and keeping an army presence.
Israel's defence minister has said that Israeli troops would not stay in Gaza - but nor would they leave the area.
"It doesn't mean we will be in Gaza, but we will stay at least around the fence [surrounding Gaza] and in the vicinity," Shaul Mofaz told journalists two weeks ago.
He admitted there was "no detailed plan for Gaza".
The senior Israeli source said the US had not agreed to pay for removing settlements - but could change its stance.
The US has shifted its position since Israeli Prime Minister Ariel Sharon first suggested a unilateral Israeli withdrawal from the Gaza Strip last year.
At first Washington said it opposed unilateral measures as being contrary to the roadmap peace plan the US has backed.
But Washington has decided that since it has always said it was opposed to Jewish settlements in Palestinian territory, it cannot now oppose removing them.
Ariel Sharon is reportedly prepared to force the issue in Cabinet
The source said the US insisted that settlers removed from the Gaza Strip not be moved en masse to the West Bank, and that Gaza evacuation would not be an excuse for annexing territory elsewhere.
On Monday, visiting Israeli Foreign Minister Silvan Shalom told journalists in London that Israel was prepared to take unilateral options - but only with US agreement.
Mr Sharon is due to discuss Israeli plans with President George W Bush and other senior US officials in Washington later this month.
The senior Israeli source said Mr Sharon was prepared to go over the head of his cabinet to the Israeli public over his withdrawal plan.
The source predicted that a proposed national referendum on the plan would pass "possibly with a huge majority" and that the Knesset would also approve it.
That could enable Mr Sharon to push it through his right-wing cabinet, the source said.
There have been reports that Israel wants Egypt to take control of part of the Gaza Strip if Israel withdraws.
Israeli Foreign Minister Silvan Shalom is heading to Cairo next week to meet President Hosni Mubarak.
But the Israeli source said the Egyptians "are not willing to become the new keepers" of Gaza.
Israel is concerned that the Islamic militant group Hamas will take control of Gaza if Israel withdraws, making the flow of illicit arms impossible to control.
Egypt is also reportedly worried that the spread of Hamas' power in Gaza will influence Islamic fundamentalists in Egypt and destabilise Hosni Mubarak's government.