The elder son of Libyan leader Colonel Muammar Gaddafi, Mohammad, who was captured by the rebels earlier on Monday, has escaped, Al Jazeera said.
Mohammad, who was arrested in his house during an interview with Al Jazeera, fled with the help of one of the rebels.
Two more of Colonel Gaddafi's sons, Saif al-Islam and Saadi, were also arrested earlier in the day, while their father's whereabouts is still unknown.
Fresh clashes between the rebel troops and security forces loyal to Gaddafi erupted on Sunday on the outskirts of the Libyan capital, Tripoli.
Early on Monday, rebels gained control of the Libyan capital and occupied the main square.