After the worst day of violence between security forces and ultranationalists, and the Israeli leader saying he had ordered "every necessary step" to be taken, the army has declared the Gaza Strip's Jewish settlements a closed zone.

The Israeli army on Thursday declared the Gaza Strip's Jewish settlements a closed military zone.

An army spokeswoman said the measure was temporary.

Security sources said the decision to prevent Israelis - other than residents - from entering all 21 Gaza settlements was intended to prevent an additional influx of ultranationalists who have attacked Palestinians and security forces in the area in the past few days.

Also on Thursday, Prime Minister Ariel Sharon lashed out at far right Jews in newspaper interviews after a day of clashes between security forces and anti-withdrawal activists in Gaza and on Israel's highways.

Far right Jews bent on scuttling a plan to evacuate all 21 Jewish settlements in the occupied Gaza Strip and four of 120 in the West Bank in August continued their campaign against the withdrawal.

"Every incident of this sort of rampaging must stop. I have given clear instructions. We will take every necessary step so that life in Israel proceeds normally," Sharon told the daily Yedioth Ahronoth.

In Wednesday, anti-Arab Kach radicals squatting in a house in a Palestinian district outside the Gush Katif settlement seriously wounded a Palestinian youth by throwing rocks at his head from close range during stone-throwing clashes.

Arrests

Israeli soldiers later stormed the building and ousted the Kach members, mainly youths, who had been intent on establishing a stronghold of resistance to the planned settler evacuation.

Thirty rightists were arrested.

Israeli police also arrested 150 anti-pullout demonstrators who tried to block highways around Israel during Wednesday's evening rush hour.

Sharon, in an interview with the Haaretz daily, called the assault on the Palestinian youth "an act of savagery, vulgarity and irresponsibility. We cannot let a small group of law breakers impose a reign of terror".

Opponents of Sharon's plan to "disengage" from conflict with the Palestinians seeking statehood have threatened to bring Israel to a halt ahead of the pullout.

Threats

Some ultranationalists have also threatened violence, and the lives of Sharon and the army chief of staff.

"They have said they will set the country on fire. They won't set anything on fire. Every one of us must understand and fight this dangerous phenomenon," Sharon told Yedioth Ahronoth.

Israeli media said security forces would put a number of radicals under detention without trial and that judicial officials would demand harsh sentences for demonstrators blocking roads or those who throw nails on them.

Endangering human lives

On Wednesday, suspected opponents of the Gaza withdrawal threw spikes and spilled oil on the Tel Aviv-Jerusalem highway, causing major traffic jams and at least 20 tyre blowouts.

Attorney-General Menachem Mazuz ordered the perpetrators be charged with wilfully endangering human life on the roads, a charge that carries a 20-year maximum jail term, Haaretz said

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