Jerusalem ? Prime Minister Ariel Sharon wants to shield several large Jewish settlements by extending Israel’s security barrier deep into the West Bank, but he would leave gaps in the section in hopes of defusing U.S. objections that the fence could mark a permanent border, a Sharon adviser and a settler leader said Tuesday.

The plan, denounced by Palestinians as a land grab, comes up for Cabinet approval today and is expected to pass.

In its bid to stop Palestinian bombers and other attackers, Israel has already built almost 100 miles of the barrier that will eventually stretch, depending on the route, up to four times that distance.

Portions of the barrier — a network of fences, walls, razor wire and trenches — run on West Bank land, but to date it has largely kept to the Israel-West Bank dividing line known as the “Green Line,” diverting in some places a few miles into the West Bank to enclose Jewish settlements.

Under the new proposal the barrier would veer almost 20 miles into the territory, cutting the northern section of the West Bank in two for much of its width.

Israel says the barrier is necessary to stop bombers who have killed more than 400 people in three years of fighting — and it points to the success of a fence already in place for years around the Gaza Strip, where no bombers have crossed.

The Arab community of Marda is seen in the distance through a monument overlooking the valley from the Jewish West Bank settlement of Ariel. A planned security fence around Ariel that would protrude 20 miles into the West Bank threatens to further undermine Israeli-Palestinian relations.