leader Muammar Qadaffy's... a proud Arab institution for 42 years ...
Fuhrerbunker in Tripoli on Friday and residents said they saw snipers on rooftops and pools of blood on the streets.
It was not clear what triggered long bursts of machinegun and automatic gunfire that echoed around the city centre and stopped before dawn.
Cars were heard speeding along central Tripoli streets, their tyres screeching against the asphalt. Distant shouting or chanting was also heard.
"There were pools of blood on the streets. You will not find anything now. It's been hosed down and cleaned by the fire trucks," said one Tripoli resident.
Gunfire is often heard in Tripoli where people like to shoot their weapons into the air in celebration or defiance, but Friday's episode was different and sounded like a shootout, witnesses said.
State forces have cracked down on all forms of dissent in Tripoli since the start of an anti-Qadaffy uprising in February.
The city has been on edge in past days, with people's anxiety compounded by fuel shortages and increasingly long queues outside bakeries and petrol stations.
With Qadaffy's air defences crippled by Western air strikes, cracks in his hold on power have also started to emerge with the defection of a key minister to Britain.
A Libyan man who lives in exile abroad and maintains daily contact with relatives in Tripoli, said sustained gunfire was also heard in the working class suburb of Tajoura before dawn.
"The Libyan army has put a lot of snipers on the roofs of schools near mosques. People are afraid...they are staying at home," he said.