Regional leaders in Libya have threatened to cut off oil supplies to the West if dictator Muammar Gaddafi does not end the crackdown on protesters or leave the country.
Libya is Africa's fourth biggest oil exporter producing 1.6 million barrels a day, of which 1.1 million are exported, according to Libyan data. The price of crude jumped by more than $US1 a barrel to $US103.5 a barrel on Monday on fears the unrest could disrupt supplies.
After days of violent unrest in the eastern city of Benghazi, people have joined protests for the first time in Colonel Gaddafi's stronghold in the capital, Tripoli.
Sporadic gunfire could be heard in the capital early on Monday. The previous day, there was heavy gunfire and witnesses spoke of tear gas and live ammunition used against thousands of protesters by security forces.
In a rambling address, one of the colonel's sons, Saif al-Islam Gaddafi, warned of civil war and promised to fight the uprising to the last man standing.
"Libya is at a crossroads. If we do not agree today on reforms, we will not be mourning 84 people, but thousands of deaths, and rivers of blood will run through Libya," he said.
One of the bloodiest revolts to convulse the Arab world appears to be seriously threatening Colonel Gaddafi's 42-year grip on power.
Benghazi, Libya's second largest city, has fallen to anti-government forces after a crack army unit defected to the opposition.
Saif al-Islam Gaddafi seemed to acknowledge that Benghazi and the nearby eastern city of Baida were no longer under government control, saying civilians were driving the army's tanks.
He played down casualties, suggesting that at most 14 people have died in clashes in Benghazi.
However, medical sources have put the death toll at more than 200. A doctor told the BBC scores of casualties have been brought to the city's Jala hospital, most of them with gunshot wounds.
Witnesses say troops used machine-guns, mortars and even a missile against the mourners attending funerals of those killed in clashes on Friday.
Meanwhile, about 500 Libyans stormed and looted a South Korean construction site near Tripoli on Monday, injuring about 15 Bangladeshi and three South Korean workers, Seoul's foreign ministry said.
Diplomat resigns to join uprising
Libya's permanent representative to the Arab League has resigned his position to join the revolution unfolding in his country.
Abdel Moneim al-Honi says he did it in protest at the acts of violence and repression against the demonstrators.
There are also unconfirmed reports that members of the Libyan army have defected and joined the revolt.
Reports are difficult to verify, however, because of severe media restrictions. Foreign media are not allowed in Libya and web analysts say internet traffic from there has been throttled in recent days.
Parts of the Middle East and Northern Africa are experiencing a wave of pro-democracy protest, fuelled by the fall of Egypt's Hosni Mubarak on 11 February, and long-time Tunisian President Zine al-Abidine Ben Ali in January.
