23:12 Anti-Gaddafi protesters in streets of Tripoli, explosions and gunfire heard from multiple locations, according to local residents.
23:48 Tripoli residents receive mobile phone text messages urging them to "go out into streets to eliminate agents with weapons" according to a local resident who spoke to the Reuters news agency.
Al Jazeera Live Blog - hat tip Hot Air.
Breaking rumor: Libyan TV reporting Qaddafi has fled with two sons. Engel of NBC.
August 21st: Al Jazeera liveblog: Rebels have entered the Green Square in Tripoli and are being greeted by crowds. A military post was overrun on the outskirts of Tripoli, some prisoners were freed and weapons seized. In Tripoli, prison guards are said to have released prisoners and asked forgiveness for doing their job. The Libyan Interior Minister arrived unheralded by plane in Cairo and says he is there as a tourist. Praetorian guard charged with Qadaffi's personal security has surrendered. There's a hodgepodge of fighters involved - some allied with the National Transition Council, some are Islamist groups on their own and there may be Berber tribesmen from the south too.
Son, Mohammed, was being interviewed by phone when shots rang out inside his own home. Audio clip here.