A security official said four people were slightly hurt. Dust was still rising from the rubble when reporters arrived at the scene after midnight.

Gadhafi’s whereabouts at the time of the attack on his sprawling Bab al-Aziziya compound were unclear. He has made infrequent public appearances in Tripoli during the fighting that broke out in February between his forces and rebel groups.

The strike on the compound — a military base where Gadhafi maintains an official residence — was a sign of mounting pressure on the regime. While NATO said the site was targeted as a military command post, it also delivered a strong message to the embattled leader that the alliance is widening its range of targets.

While rebels control most of eastern Libya, Gadhafi is trying to keep control of the western half, which includes the capital of Tripoli. In recent days, opposition forces in western Libya drove Gadhafi’s troops out of the besieged rebel city of Misrata and also took control of a border crossing with Tunisia.

Gadhafi’s troops on the outskirts of Misrata unleashed more shells into the city Monday following an especially bloody weekend that left at least 32 dead and dozens wounded. The latest shelling hit a residential area and killed 10 people, including five members of one family, according to a doctor in Misrata who spoke on condition of anonymity because he feared government retaliation.

The battle for Misrata, which has claimed hundreds of lives in the past two months, has become the focal point of the armed rebellion against Gadhafi since fighting elsewhere is deadlocked.

Video of Misrata civilians being killed and wounded by Gadhafi’s heavy weapons, including Grad rockets and tank shells, have spurred calls for more forceful international intervention to stop the bloodshed.

In Brussels, a NATO spokesman said the alliance is increasingly targeting facilities linked to Gadhafi’s regime.

"We have moved on to those command and control facilities that are used to coordinate such attacks by regime forces," the spokesman said of the strike on Bab al-Aziziya, which was hit last month, early in the NATO air campaign. The official spoke on condition of anonymity in line with military briefing regulations.

Gadhafi’s son, Saif al-Islam Gadhafi, struck a tone of defiance. He claimed Gadhafi has "millions of Libyans with him" and said NATO’s mission was doomed to fail.

"In history, no country has achieved victory with spies and traitors and collaborators. … NATO, you are the losers," he was quoted as saying by the state news agency JANA.

The Libyan government said it has been in touch with Russia, China, Turkey, Italy and other countries concerning the NATO strike. The foreign governments were told that "message sent by NATO in the early hours of this morning was sent to the wrong address," according to government spokesman Moussa Ibrahim.

In Washington on Sunday, three members of the Senate Armed Services Committee said more should be done to drive Gadhafi from power, including targeting his inner circle with airstrikes. Gadhafi "needs to wake up every day wondering, ‘Will this be my last?’" Sen. Lindsey Graham, a Republican on the committee, told CNN’s "State of the Union."

In last month’s attack on Bab al-Aziziya, a cruise missile blasted an administration building, knocking down half of the three-story building. The U.S. bombed the compound in April 1986, after Washington blamed Libya for an explosion at a Berlin disco that killed two U.S. servicemen.

At least two of the guided bombs struck Bab al-Aziziya early Monday, and the booms could be heard miles (kilometers) away.

A multistory building that guards said served as Gadhafi’s library and office was turned into a pile of twisted metal and broken concrete slabs. Dozens of Gadhafi supporters climbed atop the ruins, raising Libya’s green flag and chanting support for their leader.

A second building, where Gadhafi received visiting dignitaries, suffered damage. The main door was blown open, shards of glass were scattered across the ground and picture frames were knocked down.

Just two weeks ago, Gadhafi had received an African Union delegation led by South African President Jacob Zuma in the ceremonial building, which was furnished with sofas and chandeliers. The delegation had called for an immediate cease-fire and dialogue between the rebels and the government.

NATO’s mandate from the U.N. is to try to protect civilians in Libya, split into a rebel-run east and a western area that remains largely under Gadhafi’s control. While the coalition’s airstrikes have delivered heavy blows to Gadhafi’s army, they have not halted attacks on Misrata, a city of 300,000 people.

Still, in recent days, the rebels’ drive to push Gadhafi’s men out of the city center gained momentum.

Late last week, they forced government snipers out of high-rise buildings. On Sunday, rebels took control of the main hospital, the last position of Libyan troops in the center of town, said a resident who asked to be identified only by his given name, Abdel Salam, for fear of reprisal. Still, government forces shelled the city, he said.

"Now Gadhafi’s troops are on the outskirts of Misrata, using rocket launchers," Abdel Salam said.

A Misrata rebel, 37-year-old Lutfi, said there had been 300-400 Gadhafi fighters in the main hospital and nearby neighborhoods that were trying to melt into the local population.

"They are trying to run way," Lutfi said, speaking on condition of anonymity for fear of reprisal. "They are pretending to be civilians. They are putting on sportswear."

Ali Misbah, a captured Libyan soldier who had been wounded in the leg, was held under guard in a tent in the parking lot of the Al Hikmeh Hospital, one of the city’s smaller medical centers.

Misbah, 25, said morale was low among Gadhafi’s troops.

"Recently, our spirit has collapsed and the forces that were in front of us escaped and left us alone," he said,adding that he and his fellow soldiers were told they were fighting al-Qaida militants, not ordinary Libyans who took up arms against Gadhafi.

"They misled us," Misbah said of the government.

Deputy Foreign Minister Khaled Kaim has said the military is withdrawing from the fighting in Misrata, ostensibly to give a chance to local tribal chiefs to negotiate with the rebels. He said the tribal chiefs were ready to send armed supporters to fight the rebels unless they lay down their weapons.

Rebels dismissed government claims that tribes in the area were siding with Gadhafi and that troops were redeploying voluntarily.

"It’s not a withdrawal. It’s a defeat that they want to turn into propaganda," said Dr. Abdel-Basit Abu Mzirig, head of the Misrata medical committee. "They were besieging the city and then they had to leave."

Daily life in Libya has grown more difficult since the uprising, with prices of goods skyrocketing.

Lines for gasoline are growing longer in the oil-rich country, with some drivers saying it takes days to reach the pump and others reporting that punches have been thrown and guns have been drawn as tempers flared among motorists.

A driver in the town of Zuwara said he had been waiting in line for five days. Along the coastal road outside the capital of Tripoli, every gas station had huge lines stretching for hundreds of yards, six cars wide.

A doctor in Tripoli said all the gas lines that he has seen have also had security forces to keep order.

"It is very tense," he said, saying he saw fights break out over someone cutting ahead in line, with men shouting, brawling and kicking car windows. Sometimes security men intervene, but other times they just watch, said the doctor, who spoke on condition of anonymity because he feared government retaliation.

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Hadid reported from Cairo. Associated Press writers Ben Hubbard in Benghazi, Libya, Sebastian Abbot in Ajdabiya, Libya, Hadeel al-Shalchi in Cairo and Slobodan Lekic in Brussels contributed to this story.