On Saturday night, the promise was put to the test. According to rebel sources in the capital and opposition groups abroad, including in the Tunisian resort town of Djerba, "Operation Mermaid Dawn" was launched from the Ben Nabi Mosque on Sarim Street near the heart of the city.
"Mermaid" is a long-standing nickname for Tripoli.
The rebels moved just after Iftar, the breaking of the Ramadan fast.
A group of young men began chanting Allahu akbar, God is Great, signifying the start of a new protest at the mosque, witnesses in Tripoli and rebels said. Prayers were cancelled and all women sent home. The men then locked themselves in and began shouting anti-Gaddafi slogans.
They then used the mosque's loud speaker system, normally used to call people to prayer, to broadcast their chants across the city.
As shooting and explosions lit up the Tripoli night, Gaddafi forces arrived and initially opened fire on the mosque with machine guns, also summoning reinforcements armed with anti aircraft guns mounted on pick up trucks. The men inside the mosque were unarmed.
Local residents and rebel fighters then converged on the mosque to defend it, using machine guns and Molotov cocktails in a fierce firefight. The rebel forces were able to drive the Gaddafi forces back forcing them to take refuge in the state TV centre on Al Nasr Street nearby.