Scuffles erupted today between Israeli right-wing protesters and police who surrounded a campsite set up as a base for a mass march on the Gaza Strip to try to disrupt Israel's withdrawal in mid-August.
Witnesses said at least 20 demonstrators were arrested by police at the entrance to the Kfar Maimon farming village, about 15 kilometres from the Gaza Strip.
About 15,000 right-wingers in the area were planning to march on Gaza settlements despite a police ban on their demonstration.
"This protest is illegal. The event is over. We are offering bus rides back to your homes," police shouted through loudspeakers at the protesters, many dressed in orange shirts, a symbol of opposition by right-wingers to the Gaza pullout.
The demonstrators had gathered at Kfar Maimon after making their way past police blockades yesterday. Officials pledged to stop them from advancing further toward the Gush Katif settlement bloc where they planned a mass protest.
Hundreds of police and soldiers surrounded the protesters' tents as they slept, and a tense standoff began at daybreak this morning.
Israeli security forces declared the area near the Gaza Strip to be a closed military zone to prevent ultranationalists from pouring into the Gaza settlements to resist the withdrawal scheduled to begin in mid-August.
The showdown comes against a backdrop of resurgent Israeli-Palestinian violence and fresh clashes in Gaza between Hamas militants and Palestinian security men - developments that could complicate next month's evacuation of Gaza settlers.
The Gaza withdrawal, which Mr Sharon has billed as "disengagement" from conflict with the Palestinians, has angered right-wingers who say Israel is giving up a Biblical birthright and rewarding a Palestinian uprising.
Palestinians welcome any pullout but fear Mr Sharon is trading tiny Gaza for a tighter grip on larger West Bank settlements that house most of Israel's 240,000 settlers. About 8,500 Jews live cloistered from 1.3 million Palestinians in Gaza.
Israeli troops earlier killed two Palestinians during a raid near the West Bank town of Jenin.