Libya's unrest spread to the capital Tripoli on Sunday after scores of protesters were killed in the second city Benghazi, which appeared to have slipped out of control of forces loyal to Gaddafi.
According to credible reports, at least 233 protesters were killed in the protests against the dictatorial regime of Muammar Gaddafi.
In the first sign of serious unrest in the capital, thousands of protesters clashed with supporters of Gadaffi in Tripoli. Gunfire could be heard and police using tear gas to disperse the demonstrators. In Benghazi, the centre of Libya's unrest, tens of thousands of people took to the streets and appeared to be in control of the city before security forces opened fire and killed scores.
Benghazi residents said soldiers from a unit had joined their protest and defeated a force of Gaddafi's elite guards. Bodies were brought to a hospital riddled with bullets and wounds from rocket-propelled grenades.
A witness in Tripoli said police in the capital were using tear gas against protesters, some of whom were throwing stones at billboards of Gaddafi.
The US State Department said it had raised strong objections with Gaddafi's government about the "use of lethal force against peaceful demonstrators".
With Washington stepping up pressure on Tripoli, one of Gaddafi's sons, Saif al-Islam, said on state television that his father would fight against the popular uprising to "the last man standing".
Obama's administration also signalled that the Libyan government might face consequences if it did not take heed of warnings to rein in its security forces and respect its citizens' right to protest.
"We are considering all appropriate actions," the US official said, without elaborating.
EU High Representative Catherine Ashton issued a statement on Sunday, condemning the repressions against peaceful demonstrators and deploring the violence and the death of civilians.
"The legitimate aspirations and demands of the people for reforms must be addressed through open and meaningful Libyan-led dialogue," said Ashton in a statement released after a meeting of EU foreign ministers.
Ashton also called on the Libyan authorities to immediately cease the blocking of the Internet and the mobile telephone network, as well as to allow the media to work freely trough the country.
Libya has told the European Union it will stop cooperating on illegal migration if the EU continues to encourage pro-democracy protests in the country, the bloc's Hungarian Presidency said on Sunday.
"The Hungarian ambassador was called in Libya on Thursday and was given the message that Libya is going to suspend cooperation with the EU on immigration issues if the EU keeps making statements in support of Libyan pro-democracy protests," a spokesman for Hungary, which holds the EU's rotating six-month presidency, said.
Italian Foreign Minister Franco Frattini said Italy, which has widespread business interests in Libya, particularly in the energy sector, was concerned about developments.
"We are following very closely all the situation. Italy as you know is the closest neighbour, both of Tunisia and Libya, so we are extremely concerned about the repercussions on the migratory situation in the southern Mediterranean," he said.
Libya has frequently threatened to cancel cooperation with the EU on illegal migration in the past. In December, a minister said Libya would scale back efforts to stem the flow of migrants unless the EU paid five billion euros a year.
The International Organisation for Migration estimates that migrants from across Africa account for about 10% of Libya's six million population, although only a minority of those attempt to travel on to Europe to find work.
Tens of thousands of illegal migrants try to make the journey from the northern coasts of Tunisia and Libya to islands off Italy every year, with hundreds having to be rescued by Italy's coastguard and housed in migration centres.
Libya is a major energy producer with significant investment from Britain's BP, Exxon Mobil of the United States and Italy's ENI among others.
(EurActiv with Reuters.)