Israel restricts chemical sales

The entry and sale of urea, nitric acid, sulphuric acid and potassium nitrate will all be subject to the new regulations.

The announcement came as Israeli tanks with helicopter support entered a Palestinian refugee camp in the West Bank town of Jenin in a search for alleged militants.

Shots were exchanged, but there was no immediate report of casualties or arrests. However, five Palestinians were reportedly arrested in the southern West Bank town of Hebron.

Israeli Defence Minister Binyamin Ben-Eliezer said the operation did not mean that last week's security agreement with the Palestinians had been suspended.

Under the deal, Israel was to scale down its military presence in some Palestinian areas in return for tougher action to stop suicide bombings.

Israeli troops have already pulled out of Bethlehem, but the Palestinians have accused them of delaying a planned withdrawal from Hebron.

Israeli military sources said that two mortar shells were fired at Jewish settlements in the south of the Gaza Strip, but no-one was injured.

Explosive devices

Palestinians who want to buy the chemicals listed, for both commercial and private purposes, will now need a permit from the Israeli military. Without permission, the army will confiscate the chemicals.

The chemicals are routinely used in fertilisers, and the Palestinian Authority has told the BBC that the restrictions will damage fruit and vegetable production and affect the winter olive harvest in the West Bank.

A statement from the Israeli army said the move was part of "the war against terrorist infrastructure".

"This measure was taken because terrorist organisations utilise chemical materials to prepare explosive devices," the statement said.

Correspondents say the army clearly believes that common chemicals have gone into the production of explosives used by suicide bombers attacking Israeli targets.

This is the first time the Israel authorities have restricted their sale.

The measure is part of a series of Israeli moves designed to prevent attacks against Israel. Over the last few months these have included extensive military curfews, travel bans and the demolition of suicide bombers' homes.

Palestinian militant groups like Hamas and Islamic Jihad have wreaked havoc in Israel since the intifada began more than a year-and-a-half ago, launching repeated suicide attacks on Israeli targets.