Prime Minister Ariel Sharon on Wednesday signed an order closing all of Gaza's 21 settlements to non-residents after ultranationalists announced plans for a march that could have brought an influx of thousands of pro-settler protesters in coming days.

The closure by the army - the second in recent weeks - enraged settler leaders, who may now step up anti-pullout demonstrations within Israel.

The army closed off the Gaza settlements on 30 June after days of violence between settlers and security forces as well as Palestinians.

Rightist opponents to Sharon's plan, which he has billed as "disengagement" from conflict with the Palestinians, have blocked highways and planted fake bombs.

"This is an incomprehensible act," settler council chief Avner Shimoni said of the closure. "Is there no democracy?"

Israel declared a closed military zone to prevent more settler supporters from swarming in and hunkering down to reinforce Gaza settlers vowing to resist eviction in mid-August.

Security officials fear that a hardcore of activists could turn violent, though most settlers have promised only passive resistance.

"The situation required it," one government source said after the border was sealed.

Support

Cars and trucks quickly backed up at a main crossing between Israel and Gush Katif, Gaza's largest settlement bloc, with irate drivers waving identity cards at police and demanding to be let through. 

Most Israelis support Sharon's
pullout plan, a poll shows

Polls show most Israelis support the pullout, which Sharon says will boost the Jewish state's security after nearly five years of conflict.

But rightist opponents, many of whom claim a biblical birthright to Gaza and the occupied West Bank, claim it is a gift to "Palestinian militants" who have spearheaded attacks during an uprising against Israeli occupation.

Sharon's plan calls for removing all of Gaza's settlements and four of 120 enclaves in the West Bank, territories Palestinians want for a future state.

Between 8000 and 9000 settlers live in Gaza, cloistered from more than 1.3 million Palestinians.

The International Court of Justice has said Israel's settlements are illegal under international law. Israel disputes this.

Foreigners taken hostage

In a separate development on Wednesday, two engineers from Britain and Austria were being held at a refugee camp in the Gaza Strip after being taken hostage by a Palestinian family trying to secure the release of their jailed relatives. 

A fellow employee of the two men, who asked for the pair not to be identified, said they had been abducted overnight from outside their house in Gaza City.

"We can confirm that two foreigners have been kidnapped and are being held at the Buraij camp by members of a family. It is not related to any political activity but a family dispute"

Palestinian Interior Ministry spokesman

British diplomats said they were liaising with the Palestinian
Authority (PA) to secure the pair's release. 

A spokesman for the Palestinian Interior Ministry confirmed that the pair were being held at the Buraij refugee camp, to the south of Gaza City. 

"We can confirm that two foreigners have been kidnapped and are being held at the Buraij camp by members of a family. It is not related to any political activity but a family dispute," the
spokesman said.

Security sources said the family behind the abductions was trying to put pressure on the PA to secure the release of seven of their relatives who are currently in prison for activity that is not related to the conflict with Israel.