A Libyan soldier looks at a damaged building at Libyan leader Moammar Gadhafi's Bab Al-Aziziya compound in Tripoli on Monday. (Louafi Larbi/Reuters)

NATO airstrikes targeted the centre of Moammar Gadhafi's seat of power early Monday, unleashing guided bombs that destroyed a multistorey library and office in his compound and badly damaged a reception hall for visiting dignitaries.

A government official said at a news conference at the site that three people had been killed and 45 injured, 15 of them seriously.

However, a security official had told journalists when they first visited the scene hours earlier that only four people had been slightly injured. There was no immediate explanation for the discrepancy.

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.

Government spokesman Moussa Ibrahim said Gadhafi is not in hiding.

"He is well. He is healthy. He is in high spirits," said Ibrahim, adding that officials considered the airstrike an attempt on Gadhafi's life and "an act of terrorism."

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.

In Rome Monday, Prime Minister Silvio Berlusconi's office announced that Italy will take part in bombing raids of some military targets in Libya. Previously, Italy had largely restricted its role in Libya to enforcing the no-fly zone.

Attacks in Misrata continue

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 an entire family, according to a doctor in Misrata who spoke on condition of anonymity because he feared government retaliation. Mourners later carried six crudely constructed coffins of family members to a funeral near a mosque.

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.