Firefighters were still working to extinguish flames in part of the ruined building a few hours after the attack, when foreign journalists were brought to the scene in Tripoli.
The press official, who asked not to be identified, said 45 people were hurt in the strike, 15 of them seriously, and some were still missing. That could not be independently confirmed.
Gaddafi’s son Saif al-Islam said the Libyan government would not be cowed by such attacks.
“The bombing which targeted Muammar 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 Jana state news agency.
“You, NATO, are waging a losing battle because you are backed by traitors and spies. History has proved that no state can rely on them to win.”
Gaddafi’s compound has been hit before, but NATO forces appear to have stepped up the pace of strikes in Tripoli in recent days. A target nearby, which the government called a car park but which appeared to cover a bunker, was hit two days ago.
The United States, Britain and France say they will not stop their air campaign over Libya until Gaddafi leaves power.
Washington has taken a backseat role in the air war since turning over command to NATO at the end of March but is under pressure to do more. Last week it sent Predator drone aircraft, which fired for the first time on Saturday.
MISRATA BOMBARDED
Government troops bombarded the western rebel bastion of Misrata again on Sunday, two days after announcing their withdrawal following a two month siege.
An engineer who works for a dissident radio station in Misrata told Al Arabiya television that at least 30 people had been killed and 60 wounded by the shelling in the coastal city.
The number of dead could not be independently verified.
“There is very intense and random shelling on residential areas. Burned bodies are being brought into the hospital,” Ahmed al-Qadi told Al Arabiya.
A doctor in a hospital in Misrata said that among the dead from what he called heavy artillery and mortar shelling was a 10-year-old boy killed while he was sleeping at home.
A government spokesman said the army was still carrying out its plan to withdraw from the city, but had fired back when retreating troops were attacked.
“As our army was withdrawing from Misrata it came under attack by the rebels. The army fought back but continued its withdrawal from the city,” Mussa Ibrahim told reporters.
The government says its army is withdrawing and sending in armed tribesmen instead. Rebels say the announcement may be part of a ruse to mask troop movements or stir violence between rebels and locals in nearby towns.
Rebel leader Mustafa Abdel Jalil told a news conference in Kuwait that the Gulf state had agreed to give 50 million Kuwaiti dinars to his rebel council to help pay workers in the eastern part of the country under its control.
“This amount will help us a lot in paying the salaries of employees who did not receive their little salaries for two months,” he said. “We are capable of only covering 40 percent of this amount. We are in need of urgent aid.”
The rebels have been seeking international recognition as well as material support from the west and the Arab world.
Hampered by their lack of firepower, equipment and training, they have been unable to advance from eastern Libya but are fighting back and forth with Gaddafi’s troops on the coast road between the towns of Ajdabiyah and Brega.
Abdel Jalil also said the rebels had received weapons from “friends and allies”, but did not name them.
At least three people were killed in the mountain town of Zintan, around 160 km (100 miles) southwest of Tripoli, by fire from Gaddafi’s tanks and rockets, residents said.