NATO airstrikes targeted the center of Moammar Gadhafi's seat of power early Monday, destroying a multi-story library and office and badly damaging a reception hall for visiting dignitaries.

Gadhafi's whereabouts at the time of the attack on his sprawling Bab al-Azizya compound were unclear. A security official at the scene said four people were lightly hurt.

Monday's strike came after Gadhafi's forces unleashed a barrage of shells and rockets at the besieged rebel city of Misrata, in an especially bloody weekend that left at least 32 dead and dozens wounded.

The battle for Misrata, which has claimed hundreds of lives in the past two months, has become the focal point of Libya's 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 the rebel-held city.

In Washington on Sunday, three members of the Senate Armed Services Committee said that more should be done to drive Gadhafi out of power, including targeting his inner circle with air strikes. 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."

Early in the campaign of airstrikes against Gadhafi, a cruise missile blasted an administration building in Bab al-Azizya last month, knocking down half the three-story building. The compound was also targeted in a U.S. bombing in April 1986, after Washington held Libya responsible for a blast at a Berlin disco that killed two U.S. servicemen.

At least two missiles struck Bab al-Azizya early Monday, and the booms could be heard miles (kilometers) away.

A multi-story 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 in support of their leader.

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