Fire raged yesterday at the People's Hall, the main building for government gatherings where the country's equivalent of a parliament holds sessions several times a year, the pro-government news website Qureyna said.
It also reported the first major sign of discontent in Gadhafi's government, saying Justice Minister Mustafa Abdel-Jalil resigned to protest the "excessive use of force" against unarmed demonstrators.
There were reports of ambassadors abroad defecting. Libya's former ambassador to the Arab League in Cairo, Abdel-Moneim al-Houni, who resigned his post Sunday to side with protesters, demanded Gadhafi and his commanders and aides be put on trial for "the mass killings in Libya."
"Gadhafi's regime is now in the trash of history because he betrayed his nation and his people," al-Houni said in a statement.
A Libyan diplomat in China, Hussein el-Sadek el-Mesrati, told Al-Jazeera, "I resigned from representing the government of Mussolini and Hitler."
Two Mirage warplanes from the Libyan air force fled a Tripoli air base and landed on the nearby island of Malta, and their pilots — two colonels — asked for political asylum, Maltese military officials said.
A protest march Sunday night sparked scenes of mayhem in the heavily secured capital. Protesters had streamed into Green Square, all but taking over the plaza and surrounding streets in the area between Tripoli's Ottoman-era old city and its Italian-style downtown.
That was when the backlash began, with snipers firing from rooftops and militiamen attacking the crowds, shooting and chasing people down side streets, according to witnesses and protesters.
Gadhafi supporters in pickup trucks and cars raced through the square, shooting automatic weapons. "They were driving like madmen searching for someone to kill. ... It was total chaos, shooting and shouting," said a 28-year-old protester.