Libya’s government accused NATO on Monday of trying to assassinate Moammar Gaddafi after the coalition sent at least two large guided bombs into the sprawling office, residential and military complex where he lives in the heart of Tripoli, destroying offices and a library used by the Libyan leader.

In a statement, the alliance described the attack, in the early hours of Monday, as a “precision strike” on a communications headquarters “that was used to coordinate attacks against civilians.” Libyan officials said it was an attempt to assassinate Gaddafi.

“We are regarding it as an attempt to assassinate the leader and unifying figure of this country and other political leaders of this country,” government spokesman Moussa Ibrahim said in a news conference in front of the ruined buildings on Monday, describing it an act “worthy of the mafia, of gangs, but not of governments.”

“How is this act of terrorism protecting civilians in Libya? How is this act of terrorism helping establish peace in Libya?” he asked. “Targeting political leaders will only help make the situation worse.”

The Obama administration denied that the strike was specifically intended to kill Gaddafi himself. White House spokesman Jay Carney, asked about the attacks in central Tripoli, said it was not U.S. policy to bring regime change to Libya.

“The goal of the mission is clear: protect the civilian population, enforce the no-fly zone, enforce the arms embargo,” Carney told reporters in Washington. While it up to NATO to select targets for air strikes, he said, it is “certainly not the policy of the coalition, of this administration to decapitate, if you will, or to effect regime change in Libya by force.”

About 130 miles east of the capital, the rebel-held port city of Misurata came under heavy shelling Monday for the third day in a row from Gaddafi loyalist forces camped out on the southern and southwestern outskirts, said Mohamed Ali, a rebel spokesman. By 5 p.m. local time, he said, at least 12 people had been killed and more than 22 injured in the latest barrages, which began overnight.

Gaddafi’s forces have intensified their shelling and rocketing of Misurata in the three days since the government said it was lifting the siege. As a result, the death toll has been climbing at one of its highest rates since the battle for Misurata began two months ago.

In another development, Italian Prime Minister Silvio Berlusconi announced that Italy will take part in air strikes on Libya to help strengthen the mission of protecting civilians. Italy had previously said it wouldn’t participate in the bombing, although it has provided other support.

Also on Monday, the first shipment of food aid from U.S. farms bound for Libya arrived in Alexandria, Egypt, U.S. officials said. The aid will be stored inside and outside Libya by the World Food Program, for use if the situation deteriorates, officials said.

“There’s concern the [food] supply chain will start breaking down” if Libyan troops continue their offensive against rebel-held towns, Mark Bartolini, director of the U.S. Office of Foreign Disaster Assistance, told reporters.

The NATO attack in Tripoli was the second against the sprawling Bab al-Aziziyah complex since Western powers began a campaign of airstrikes last month. It came hours after Sen. Lindsey O. Graham (R-S.C.) said NATO should “cut the head of the snake off” and that Gaddafi and his entourage should wake up every day “wondering ‘will this be my last?’ ”

Part residence for Gaddafi, part government offices and part military base, the complex is also the scene of nightly celebrations by hundreds of civilians offering themselves as human shields to protect Gaddafi against NATO. Security and fire department officials at the scene said no one had been badly hurt, but Ibrahim said three people were killed and 45 injured, 15 critically, all of them officials and civilians.

Gaddafi's son, Saif al-Islam Gaddafi, said the Libyan government would not be cowed.

“The bombing which targeted Moammar Gaddafi's office today . . . will only scare children. It's impossible that it will make us afraid or give up or raise the white flag,” he was quoted as saying by the state-run JANA news agency.

“You, NATO, are waging a losing battle because you are backed by traitors and spies,” he said. “History has proved that no state can rely on them to win.”

Reporters in Tripoli first heard two huge explosions and saw a red flash from the direction of Gaddafi’s compound. There was also a third, smaller explosion, which officials said was an attack on a state television broadcasting facility in Tripoli, after which the signal from all three channels went down briefly.

Later, reporters were taken to see the scene of the main attack and shown a destroyed building that officials said contained offices and a library used by Gaddafi. Its roof was caved in, many of its walls had collapsed, and shattered masonry, twisted metal and other debris were strewn over a large area.

A fire engine trained water on part of the building, while civilian supporters of the government, let in with members of the media, clambered on the rubble, chanted pro-Gaddafi slogans and waved their green flags as thick cement dust swirled through the air.

An adjacent building, where Gaddafi met South African President Jacob Zuma and a delegation of four other African presidents looking to broker a peace deal earlier this month, was also badly damaged, with the wreckage of chandeliers, furniture and picture frames spread amid the rubble.

It appeared doubtful that Gaddafi would have frequented such an obvious target, given the threat from NATO warplanes. In any case, he is believed to have built an underground bunker complex at his residence. He has rarely been seen in public since coalition airstrikes began on March 19, two days after a U.N. Security Council resolution authorized military intervention against the Gaddafi regime to protect civilians.

Ibrahim said Gaddafi was working as usual from a safe place in Tripoli, was very healthy and “in high spirits”.

NATO has been regularly aiming for the government’s command and control facilities in recent weeks, as part of what it describes as a campaign to steadily and deliberately degrade “the ability of the Gaddafi regime to launch and sustain attacks against his own people.”

In a hint of the possible dual nature of the compound that was targeted, journalists were not allowed to see an adjacent building that was also damaged by the strike, a building that one bystander said was used by the military.

The attack was also not far from another building within the complex that was destroyed at the start of the air campaign, which the alliance described at the time as another command and control center.

In the early hours of Saturday morning, reporters were also taken to the scene of another twin airstrike, which appeared to hit an underground bunker complex just outside Bab al-Aziziyah.

When the bombs struck just after midnight on Monday, the initial reaction among government minders and sympathizers at the main hotel where journalists are staying was a mixture of shock and anger.

But it swiftly turned back to the usual defiance, with government minders chanting pro-Gaddafi slogans as they escorted the press to the site in a bus. At Bab al-Aziziyah, some people screamed when the bombs struck, and many left afterward, one witness said. But others regrouped in front of state television cameras to resume their singing and chanting.