Muammer Gaddafi’s four-decade grip on power in Libya appeared increasing fragile on Monday after protests against his regime reached the capital, Tripoli, and the opposition claimed to have gained control of Benghazi, Libya’s second-largest city.

The popular uprising against Colonel Gaddafi’s regime, initially centred in Benghazi and other eastern cities, swept across Libya. Clashes were reported in Tripoli, the capital, for a second day on Monday, with dozens of people reportedly killed. Exiled opposition figures and activists said they feared another violent crackdown from the regime as it sought to maintain control of the capital.

Col Gaddafi must hold Tripoli if he is to avoid becoming the third Arab leader in two months to be toppled by popular uprisings, which have already forced the presidents of neighbouring Tunisia and Egypt from office.