Libyan rebels claimed to have seized control of some parts of Tripoli on Sunday and besieged the compound of Libyan leader Moamer Gaddafi, in what opposition fighters described as "zero hour" for an uprising in the capital, DPA reported.
The rebels said demonstrators took to the streets after sunset across the capital. Shortly after, sounds of explosions rocked the city and rebels announced a "planned uprising" by the opposition.
Insurgent detained dozens of Gaddafi's forces in Tripoli, Al Arabiya channel reported.
During the clashes, Gaddafi lashed out at European countries and the rebels in an audio message, accusing them of being after the country's oil wealth.
"What did we do to France, Britain, Norway or Denmark? You want to give the oil of Libyan people to the French - (President Nicolas) Sarkozy wants our oil," Gaddafi said in his speech aired on state television.
"You who love Libya, how do you trust them to use Libya like this?"
He described the rebels and countries calling for his ouster as "rats, donkeys," and said NATO is collapsing.
State television showed video of a small group of people in Bab al-Azizya's Green Square, cheering for Gaddafi and kissing his pictures.
"The lying channels will say the speech is recorded before. Today is Ramadan 21," he said. "It is 1:40 am now, Tripoli time."
A senior official with the rebel National Transitional Council told broadcaster Al Jazeera that "zero hour has started, the rebels in Tripoli have risen up."
At least 123 rebels were killed in the Tripoli area of Tajoura, senior rebel official Mohamed al-Harizi told Al Jazeera, confirming that opposition forces are in control of the district.
There is unknown number of deaths in other parts of Tripoli, sources said.
Fighters were also in control of the Souq al-Jumaa area in the capital, one of the rebels in the area said.
Fighters were fighting Gaddafi's forces controlling Mitiga airbase in Tripoli.
In the rebel strong-hold Benghazi, thousands were gathered in the centre of the city celebrating the "uprising" inside Tripoli.
The unrest followed a series of defections from Gaddafi's regime.
Abdel-Salam Jalloud, who helped Gaddafi topple the monarchy and take power in 1969, and was for decades his powerful deputy, defected on Friday.
"You are fighting for a system that is collapsing, that has died clinically. You have hours or moments to leave the boat of treason and tyrants to the people's boat," Jalloud said on a video interview with Al Jazeera, from an unknown location in Libya.
He also called on people to begin fighting in all cities together in order to make it harder for Gaddafi.
Jalloud's departure followed the reported defections earlier in the week of oil minister Omrane Boukraa and senior security official Nassrallah Mabruk Abdullah.