JERUSALEM (AP)  --  Israel has begun laying the foundations for a new Jewish settlement deep in the West Bank -- breaking a promise to Washington while strengthening its hold on a stretch of desert it wants to keep as it draws its final borders.

The construction of Maskiot comes at a time when Israeli Prime Minister Ehud Olmert seeks U.S. backing for eventually annexing parts of the West Bank as part of a plan to set Israel's eastern border with or without Palestinian consent.

The Palestinians and Israel's settlement watchdog group Peace Now say the Maskiot construction amounts to a new attempt to push Israel's future border deeper into the West Bank. ``It's about grabbing land,'' said Yariv Oppenheimer of Peace Now.

Otniel Schneller, an Olmert adviser, confirmed Israel is building in additional West Bank areas to ensure they are not included in the lands given to the Palestinians. He said Israel needs to keep the Jordan Valley, where Maskiot is located, as a security buffer against Islamic militants based in Iraq, Iran and elsewhere.

lmert has said that if efforts to resume peace talks fail, as expected, he would annex large Jewish settlement blocs in the West Bank and draw Israel's final borders by 2008. A separation barrier Israel is building in the West Bank is to serve as the basis for the future border.

In order to ensure a Jewish majority in lands it controls, Israel plans to evacuate as many as 70,000 West Bank settlers, relocating them to the western side of the separation barrier. Israel depicts the move as a major concession, but Palestinians fear Jewish footholds like Maskiot will prevent them from being able to build a contiguous state on the evacuated lands.

Maskiot would initially house 20 families, all former Gaza settlers forced out of their homes when Israel withdrew from the coastal strip last year. Israel has promised Washington it would not build new settlements in the West Bank.

The future residents of Maskiot say their homes are being financed by right-leaning Jewish donors and the Israeli government, and that they will be renting homes built by others.

Asked about Maskiot, Stewart Tuttle, the U.S. Embassy spokesman in Tel Aviv, said such settlement activity violates U.S. policy. ``As a general principle, the U.S. government is opposed to settlement expansion,'' Tuttle said. ``Ceasing settlement expansion is one of Israel's commitments under the road map.''

At Maskiot, bulldozers have cleared the top of a hill and work crews have laid foundations for four houses. New trees have been planted on the edges of the settlement.

The first 20 families, all from the former Gaza settlement outpost of Shirat Hayam, are expected to move there in coming weeks, said regional settler leader Dubi Tal.

The Kinarti family from Shirat Hayam has moved into a temporary concrete block home in Maskiot. A knock on the door produced a man with a large skullcap who refused to comment on the construction of his new home but said he's originally from Shirat Hayam.

Another future Maskiot resident, Yossi Hazut, said he was settling in the Jordan Valley to help determine the borders of the state of Israel.

``I don't think there is even one Israeli who thinks that the Jordan Valley is not important,'' said Hazut, who is living in a nearby community until his house is ready. ``God willing, many of us from Shirat Hayam will live in Maskiot.''

Schneller, an architect of Olmert's West Bank plan, said Israel could move the separation barrier deeper into the West Bank to include Maskiot on the Israeli side.

Israel's Defense Ministry, which oversees settlement activity, confirmed it decided before Israel's March election to approve the construction of Maskiot.

The defense minister, Amir Peretz, has not tried to derail these plans, defense officials said, speaking on condition of anonymity because they are not authorized to talk to the press. Peretz, leader of the Labor Party, is seen as a leading opponent of settlement expansion, but apparently wants to avoid stirring up too many conflicts in Olmert's coalition government.

Palestinian negotiator Saeb Erekat said Israel will eventually have to decide whether it wants to build more settlements or reach a peace agreement. ``Every settlement is meant to take Palestinian land and meant to undermine a two-state solution,'' he said.