A missile totally destroyed an administrative building of Libyan leader Muammar Gaddafi's residence in Tripoli.
The building, about 50 metres from the tent where Gaddafi generally meets guests, was flattened. It was hit by a missile, Libyan spokesman Moussa Ibrahim told journalists, who were taken to the site by bus.
"This was a barbaric bombing which could have hit hundreds of civilians gathered at the residence of Muammar Gaddafi about 400 metres away from the building which was hit," Ibrahim said.
He denounced the "contradictions in Western discourses," saying: "Western countries say they want to protect civilians while they bomb the residence knowing there are civilians inside."
Scores of Gaddafi supporters rushed towards the complex at Bab el-Aziziya in the south of the Libyan capital after a rumour spread that a plane had been shot down and crashed.
"Where is the plane?" several of them, mainly youths, cried.
Smoke billowed from the residence and barracks as anti-aircraft guns fired shots.
Tripoli was rocked by powerful explosions late Sunday, of which one was heard coming from the area around Kadhafi's residence.
Gaddafi's army announced a new ceasefire on Sunday, saying it was heeding an African Union call for an immediate cessation of hostilities, but the United States accused Tripoli of breaching the truce almost immediately.
"I sincerely hope and urge the Libyan authorities to keep their word," United Nations Secretary General Ban Ki-moon said in a swift reaction during a visit to Libya's eastern neighbour Egypt.
"They have been continuing to attack the civilian population. This (offer) has to be verified and tested," he told a news conference in Cairo.
Gaddafi's regime had declared a ceasefire on Friday after UN Security Council resolution 1973 authorised any necessary measures, including a no-fly zone, to stop his forces harming civilians in the fight against the rebels.