July 2 (Bloomberg) -- An Israeli army helicopter launched a missile that almost destroyed the empty office of the Palestinian prime minister on the fifth day of an incursion aimed at getting back an abducted soldier.

The air strike indicates that Prime Minister Ismael Hania, whom Israel holds responsible for the safe return of Corporal Gilad Shalit, 19, isn't immune from attack. Shalit was seized on June 25 in an attack on a tank just outside the Gaza Strip.

``The Israeli army will continue to employ all means at its disposal against Palestinian terror infrastructure in the Gaza Strip to allow the unconditional return of Crpl. Gilad Shalit and stop terror attacks and the launching of rockets towards Israel,'' the army said in an e-mailed statement.

Israeli forces have been in Gaza since early June 28, marking the most serious military escalation since Israel withdrew from the territory nine months ago. It is the first major conflict between Israel and Hamas since the Islamic movement, that refuses to recognize the Jewish state, won Palestinian parliamentary elections in January.

The army said it conducted an aerial attack on Hania's office as well as on two outposts used by his leading Hamas- party. Palestinian security officials, speaking on condition of anonymity, said one missile was fired into the building.

At least one Palestinian was killed and three wounded in the strikes on the Hamas outposts, Palestinian medics and witnesses said. They said that one of the outposts was used by an auxiliary force employed by the Interior Ministry.

`Military Pressure'

``We will not give up on the diplomatic front but will also not ease up the military pressure,'' Interior Minister Roni Bar- On said on Israel Army Radio.

Egyptian President Hosni Mubarak has been trying to mediate an agreement that would free the soldier. Haaretz said today that Mubarak gave Hamas until the end of today to respond to a proposal that would lead to the immediate release of Shalit in return for an Israeli promise to free Palestinian prisoners in its prisons in the near future. The newspaper cited unnamed senior Palestinian officials.

The incursion into Gaza started hours after Hamas and Fatah reached an agreement to seek an independent state alongside Israel. While Hamas is formally sworn to Israel's destruction, the accord implicitly recognizes Israel's right to exist.

Hamas took over the Palestinian cabinet in March after winning the parliamentary elections. Its biggest rival, Fatah, which backs resuming peace talks with Israel, still controls the presidency and security forces. The two groups have been locked in a contest for power, a conflict that has erupted into street battles and bombings.

Release Demanded

In a leaflet faxed to reporters in Gaza City today, the three armed groups that kidnapped Shalit demanded the release of 1,000 Palestinians, Arabs and Muslims held in Israeli jails. It was unclear what they were offering in return for their release. The groups include the military wing of Hamas.

``The whole international community, including the U.S. and the European Union, everyone has called for the unequivocal and immediate release of Shalit,'' Mark Regev, spokesman for the Israeli Foreign Ministry, said by phone. ``That is our position as well.''

Ziad Abu Ein, Palestinian deputy minister in charge of prisoners, told reporters in the West Bank city of Ramallah yesterday that Shalit had three bullet wounds in his abdomen and was being treated by a Palestinian doctor.

Financial Aid

The chaos in Gaza, a 360-square-kilometre (139-square-mile) enclave stretching along the Mediterranean coast, has been compounded by the decision of Western nations to cut off financial aid to the Palestinian Authority in a bid to force Hamas to accept Israel's right to exist and foreswear violence. Without the aid, or tax transfers from Israel, the authority hasn't been able to pay civil servants, damaging the economy.

The 1.4 million residents of the Gaza Strip will face a humanitarian crisis ``within days'' unless fighting between Israelis and Palestinians stops, the head of United Nations emergency relief agency said yesterday.

To contact the reporter on this story: Gwen Ackerman in Jerusalem at gackerman@bloomberg.net

Last Updated: July 2, 2006 03:20 EDT