GAZA CITY, Gaza Strip (AP) – Israeli aircraft fired missiles at the Palestinian prime minister’s office early Sunday, just hours after a Palestinian official said the soldier whose abduction sent Israeli troops into the Gaza Strip is alive and in stable condition.

A Hamas militant was killed in another Israeli airstrike.

Witnesses said two missiles hit the Gaza City office of Prime Minister Ismail Haniyeh of Hamas early Sunday, leaving one bystander slightly injured and setting the empty building on fire. The Israeli army confirmed it attacked Haniyeh’s office.

Inspecting his burning office, Haniyeh called the Israeli attack senseless.

“They have targeted a symbol for the Palestinian people,” he said.

The strike, at about 1:45 a.m., came shortly after moderate Palestinian President Mahmoud Abbas warned Saturday that the coming hours would be “critical, sensitive and serious” for trying to calm the crisis.

Israeli aircraft also hit a school in Gaza City early Sunday, setting a building on fire, witnesses and rescue workers said. No one was hurt. Other targets were Hamas facilities in northern Gaza.

Palestinian security officials said two militants were wounded. One later died of his wounds, hospital officials said. He was the second militant killed in the five-day Israeli operation to force the release of Cpl. Gilad Shalit, the 19-year-old soldier abducted by Palestinian militants last Sunday.

Israeli planes attacked the Interior Ministry on Thursday.

Meanwhile, Ziad Abu Aen, a Palestinian deputy minister and Hamas official said Saturday that Shalit was wounded but in stable condition.

Another Hamas official, however, cast doubt on the credibility of the statement. Osama Muzami said only the military wing of the Islamic militant group knows the condition of the soldier.

There had been no sign of Shalit since he was abducted during a militant raid on an Israeli army post just outside the Gaza Strip that killed two soldiers and two of the attackers.

Abu Aen said “mediators” told him Shalit had received medical treatment for wounds he suffered in the raid and was in stable condition.

“He has three wounds,” Abu Aen said in the West Bank city of Ramallah. “I guess shrapnel wounds.” Abu Aen said. Israeli soldiers and Palestinian militants exchanged fire for several hours Saturday afternoon when Israeli tanks and bulldozers crossed into Gaza and began razing farmland east of Khan Younis. No serious injuries were reported.

The fighting took place north of the position Israeli troops occupied when they entered Gaza on Wednesday. The army said it was carrying out a limited operation in the Khan Younis area and the soldiers were expected to leave soon.

The Hamas-affiliated militants holding Shalit initially said they would trade information about him for all Palestinian women and underage prisoners in Israeli jails. The militants raised their demands Saturday, calling for an end to the Israeli offensive and the release of 1,000 other prisoners in Israel, including non-Palestinian Muslims and Arabs.

The new demand appeared aimed at rallying support in the Arab world.

Israel has ruled out any compromise, saying it would only encourage more abductions.

Israel has also blamed Syria for the kidnapping, noting it gives haven to Hamas’ top leaders. Defense Minister Amir Peretz met with senior Israeli security officials Saturday night and then called Secretary of State Condoleezza Rice to urge the Bush administration to step up pressure on Syria to work for Shalit’s release, Israeli officials said.

They spoke on condition of anonymity because they were not authorized to make a formal statement.

Egypt and other foreign mediators have been working to try to resolve the crisis, but Abbas said those efforts had yet to bear fruit mainly because it was unclear who in Hamas – the militants or the group’s leadership abroad – was authorized to make decisions about Shalit.

“The next hours are critical, sensitive and serious. And though the efforts are still ongoing, we have not reached an acceptable solution until now,” Abbas’ office said in a statement Saturday.

He sounded more optimistic at a news conference Saturday night.

“Regarding the soldier, we will surely reach an agreement. It is not a dead end. People want an acceptable solution,” said Abbas, who is from the moderate Fatah Party.

Hamas, which controls the Palestinian Cabinet after winning legislative elections in January, insisted Shalit should not be freed without a prisoner swap.

Israel “should understand that it is not easy for the Palestinian people to say, ‘OK, we can release him,’ … without a price,” said Ghazi Hamad, a spokesman for the Hamas-led Cabinet.

Prime Minister Recep Tayyip Erdogan of Turkey, a predominantly Muslim country that has close ties with Israel, called President Bush on Saturday and talked for 30 minutes about the crisis.

“The president said that the initial goal should be freeing the Israeli soldier – that is the key to ending the crisis,” said Frederick Jones, spokesman for the National Security Council at the White House.

Meanwhile, the fuel supply in Gaza dwindled after Israel cut off the flow through a pipeline. Gas stations across the territory ran dry, and human rights groups worried that if fuel shipments were not restored in the coming days, Gaza could face a humanitarian crisis as generators used to pump water and power hospitals stopped working.

Authorities have been relying on generators since an Israeli airstrike Tuesday destroyed Gaza’s only power plant, knocking out 43 percent of the territory’s electricity supply, the United Nations said. The remaining electricity comes from Israel.

The Israeli army said Israel had increased the supply of electricity to Gaza to make up for the power shortage and would work to allow food and fuel to enter in the coming days.

In addition to the fighting near Khan Younis, Israel kept up the military pressure, with aircraft and gunboats pounding open ground in Gaza that the army said militants were using to launch homemade rockets into Israel.

Although troops remained massed on the border, Israel on Thursday postponed a planned invasion of northern Gaza as international mediators sought a way out of the crisis. But with no apparent progress on the diplomatic front, it was unclear how much longer they would hold off.

AP-ES-07-01-06 2034EDT