Updated

An Israeli warplane bombed the Palestinian Foreign Ministry building in Gaza City late Thursday, collapsing part of the structure and causing widespread damage in the area, Israel's second use of a huge bomb in Gaza in as many days in its two-week offensive.

The third and fourth floors of the building were destroyed in the huge blast that shook the city and damaged houses and vehicles for a wide area around it. At least 13 people were injured, all in nearby houses. It was not known if anyone was in the ministry building when the plane struck after 1:30 a.m. (2330 GMT Wednesday).

The Israeli military confirmed it carried out an airstrike on the Palestinian Foreign Ministry, noting that it is "led by Hamas." The Palestinian foreign minister is Hamas leader Mahmoud Zahar. Israel's offensive is aimed primarily at Hamas, which claimed responsibility for a cross-border attack that resulted in the capture of a soldier.

Early Wednesday, an Israeli F-16 warplane dropped a quarter-ton bomb that killed nine members of one family in Gaza City. The Israelis were aiming for Hamas leaders, who were meeting in the house.

A Hamas militant leader who has topped Israel's most-wanted list for a decade was badly wounded and underwent four hours of spinal surgery, security officials said.

The top fugitive, Mohammed Deif, could end up paralyzed, Palestinian security officials said on condition of anonymity because they were not authorized to discuss his condition. Wednesday's blast marked the army's fourth attempt to kill Deif, held responsible for suicide bombings in Israel. In a 2002 missile strike, he lost an eye.

On Wednesday morning, Lebanese Hezbollah guerrillas captured two Israeli soldiers and killed eight in a brazen cross-border attack and skirmishes that followed. Both Hamas and Hezbollah demanded prisoner swaps with Israel. Hamas said the violence of the Lebanon-Israel border could help it achieve its goal of winning the release of Palestinian prisoners in Israel.

Israel's air force targeted the two-story house of Nabil Abu Salmiyeh, a Hamas activist and university lecturer, after getting intelligence information that the leaders of Hamas' military wing, responsible for the abduction of the soldier, were meeting there. Palestinian security officials said seven or eight top Hamas officials were present.

The bomb blast killed Abu Salmiyeh, his wife, and seven of his nine children, ages 4-18. "I heard a really loud explosion and then I felt the ceiling fall on top of me. I was buried under the rubble," said Awad Abu Salmiyeh, 19, who along with an older brother was the only family members to survive.

The bombardment brought down the house and buried residents under the rubble. Rescue workers pulled out the body of a 4-year-old child, clad in a red-T shirt, whose head was blown open by the blast and whose lower body was torn off.

Hamas initially said its leaders had emerged safely from the 2:30 a.m. attack.

But Palestinian security officials later said Deif and several other top Hamas militants were hurt in the attack.

On Wednesday, Hamas militants took over the intensive care unit at Gaza's Shifa Hospital. Several people were being treated inside, including some in critical condition, medical officials said. Black-uniformed Hamas gunmen stood guard at the entrance of the unit. A large bearded man blocked people from entering, permitting only a team of doctors and top Hamas officials such as Zahar to pass.

The guard angrily declined to say who was being treated.

Health Minister Bassem Naim said 37 people were wounded in the airstrike, three critically. Hospital officials said Raed Saad, a top Hamas operative, was among the wounded, but details of his condition weren't released.

Israeli officials accused the militants of using civilians as a shield by meeting in a private home.

"Israel is compelled to take action against those planning to unleash lethal terror attacks against Israeli citizens," said David Baker, an official in the office of Israeli Prime Minister Ehud Olmert. "Palestinian terrorist leaders continue to take refuge among and hide behind their own civilians."

As the fighting entered its third week Wednesday, Israel killed at least 14 other Palestinians in a series of airstrikes, shelling attacks and a gunfight, Palestinian officials said.

More than 60 Palestinians have been killed in the offensive, most of them gunmen, but about a dozen have been civilians. One Israeli soldier also has died, shot by fellow troops.