GAZA CITY, Gaza Strip — 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 yesterday after being wounded in an Israeli airstrike, security officials said.

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

Nine members of one family were killed in yesterday’s airstrike, with an Israeli F-16 warplane dropping a quarter-ton bomb on a home in a crowded Gaza City neighborhood. The strike was by far the deadliest in Israel’s 15-day military campaign in Gaza, launched after Hamas-allied militants kidnapped an Israeli soldier.

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

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

Abu Salmiyeh, his wife, and seven of his nine children, ages 4 to 18, all died.

“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 member 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 clad in a red T-shirt, whose head was blown open and whose lower body was torn off.

Hamas initially said its leaders had emerged safely from the 2:30 a.m. attack, but Palestinian Arab security officials later said Mr. Deif and several other leading militants were hurt.

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

The guard angrily declined to say who was being treated.

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,” an official in the office of Prime Minister Olmert, David Baker, said. “Palestinian terrorist leaders continue to take refuge among and hide behind their own civilians.”

Israel launched its military campaign after Palestinian Arab militants captured the Israeli soldier June 25. Israel has rejected demands that it release hundreds of prisoners in exchange for the soldier and has instead stepped up its offensive in Gaza.

As the fighting entered its third week yesterday, Israeli troops killed at least 14 other Palestinian Arabs in four separate incidents, including Israeli tank fire and a gunfight in the central Gaza Strip.

More than 60 Palestinian Arabs 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.