An Israeli helicopter fired a missile into the empty office of Palestinian Prime Minister Ismail Haniyeh yesterday in an apparent signal the Hamas leader could be targeted unless militants release an abducted soldier. The air strike was part of a military offensive in the Gaza Strip that has been coupled with statements from Israeli leaders that no one in the Hamas-led government should believe he was immune from attack.

?We will strike anyone who harms the citizens of Israel. No one will go unpunished,? Israeli Prime Minister Ehud Olmert told his cabinet in broadcast remarks, without mentioning Haniyeh by name.

Haniyeh was not in the office at the time of the strike, witnesses said. He arrived quickly to survey the damage to find shattered furniture and windows, and a portrait of late president Yasser Arafat blown off the wall. ?This is the policy of the jungle and arrogance,? Haniyeh told Reuters. ?Nothing will affect our spirit and nothing will affect our steadfastness.?

One Hamas member was killed in a second attack on an office used by forces loyal to the Islamic militant group, whose charter calls for Israel?s destruction. A third strike hit a Hamas school, but there were no casualties.

Israel, which pulled out of the Gaza Strip last year, sent troops and tanks into the south of the territory on Wednesday after Palestinian gunmen, some from the armed wing of Hamas, seized Corporal Gilad Shalit in a cross-border raid a week ago.

Soldier abducted

With a Palestinian humanitarian crisis looming, Israel reopened Karni, the main commercial crossing into the Gaza Strip.

Israel, which had announced Gaza?s borders would be sealed indefinitely after the soldier was abducted, also opened fuel pipelines, as Olmert stepped up threats of more military action.

?I have ordered the military and defense officials to use their power and wisdom to pursue these terrorists, and those who dispatch them, provide their ideology and sponsor them,? Olmert said. ?I reiterate ? no one will be exempt.?

Israel last assassinated top Hamas leaders in 2004, killing Sheikh Ahmed Yassin and Abdel-Aziz al-Rantissi.

Hamas officials say Haniyeh has no control over the group?s gunmen. Israeli Defense Minister Amir Peretz said last week : ?The masquerade ball is over? and Hamas political leaders? ?suits and ties could not cover up involvement in terrorism?.

After Shalit?s abduction, Israel launched air strikes against Gaza?s main power plant and road bridges and arrested senior Hamas politicians in the occupied West Bank. Serious casualties have so far been limited to two dead militants.

In his remarks to the cabinet, Olmert again rejected demands by militants for Israel to release hundreds of Palestinians from its jails in exchange for the soldier.

?These are not easy days for Israel, but we have no intention of surrendering to extortion,? he said.

Haniyeh, speaking to reporters after the helicopter strike, said: ?We are still exerting great efforts with all Arab and Palestinian parties to end this crisis. But what Israel is doing deepens the crisis.?

Palestinian President Mahmoud Abbas and Egyptian mediators have been involved in round-the-clock negotiations with Hamas in an attempt to defuse a standoff that has plunged relations with Israel to new lows and dashed hopes of renewed peace talks.

A Palestinian official quoted mediators as saying 19-year-old Shalit was alive after being treated for wounds.

Nidal al-Mughrabi

Israel could force up to 25 000 Palestinians from their homes

■ Up to 25, 000 Palestinians could be forced from their homes in northern Gaza alone if Israel decides to launch a full-scale assault on the densely populated coastal strip, the United Nations said yesterday. With the threat of a mass incursion building as Israel seeks to free a soldier kidnapped by militants a week ago, the United Nations said it had drawn up plans to provide food, medicine and shelter to tens of thousands of people.

?We estimate that 25,000 people could be forced to flee Beit Hanoun if Israel attacks in the north,? Christer Nordahl, deputy director of the U.N.?s relief agency in Gaza said. ?We?re making plans to house those internally displaced in schools and are stockpiling medicine and food supplies to ensure that we can take care of them, and others across the Gaza Strip if the need arises.?

He said Israeli troops entered Beit Hanoun, frequently used by militants to fire rockets into Israel, on Saturday and asked a family to leave before themselves withdrawing early yesterday. ?Beit Hanoun is a place that the Israeli army is likely to want to occupy and take complete control of because it wants to stop the rockets being fired from there,? Nordahl said.

Residents of Beit Hanoun, where many poor families live less than 100 metres from the Israeli border, expressed fear of a possible invasion yesterday and said they hoped Palestinian militants would defend them against assault. ?From what I hear, the militant factions will be here to protect us and will use all means possible, including suicide attacks,? said Moin al-Athamna, 24, an unemployed man who lost his left leg in Israeli-Palestinian clashes in 2000.

If Israel does attack, and Defence Minister Amir Peretz made clear yesterday that a steady escalation should be expected, the United Nations said the worst case scenario would be an assault on several fronts that leaves Gaza split into parts.

Such a scenario could see many more than 25,000 people displaced and lead to widespread problems linked to sanitation and water, food and medicine supply. ?It would make it very difficult for us to get aid through to the people who need it, creating a much wider humanitarian crisis,? Nordahl said. A humanitarian crisis has loomed over Gaza, home to around 1.4 million Palestinians, for several months but intensified in the past week after Israel bombed the territory?s power station, cutting off electricity and affecting water supplies.