Western countries have expressed concern at the rising violence against demonstrators in Libya.
The United States said it was deeply concerned by credible reports of hundreds of deaths and injuries during protests in Libya, and urged the government to allow demonstrators to protest peacefully.
"The United States is gravely concerned with disturbing reports and images coming out of Libya," State Department spokesman P.J. Crowley said. "We have raised to a number of Libyan officials ... our strong objections to the use of lethal force against peaceful demonstrators."
The State Department said US embassy dependents were being encouraged to leave Libya and US citizens were urged to defer nonessential travel to the country.
Secretary of State Hillary Clinton and US ambassador to the UN Susan Rice spoke out against brutal crackdowns on protesters in Libya and Bahrain but stopped short of calling for a change of government in any of the countries facing large protests.
British Foreign Secretary William Hague said he spoke to Seif al-Islam Gaddafi by phone on Sunday and told him that the country must embark on "dialogue and implement reforms".
European Union (EU) foreign ministers have also condemned the repression of demonstrators in Libya.
Meanwhile, Libya has told the EU 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.
EU foreign policy chief Catherine Ashton had said during a visit to the region last week that Libya should listen to what protesters were saying and "allow free expression".
EU foreign ministers met in Brussels on Sunday to discuss the uprisings across North Africa and the Gulf with the focus expected to be on Egypt and Libya, where there have been days of protests against President Muammar Gaddafi's 40-year rule.
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 southern Mediterranean," he said.
Italian oil giant Eni has invested heavily in the oil-and-gas rich country. Libya's central bank, meanwhile, has a 4 percent share in Italy's largest bank UniCredit, which last year won the first international license to operate in the North African country.
Premier Silvio Berlusconi, who has hosted Gaddafi lavishly on his frequent visits to Rome, said on Saturday he was concerned about the situation but had not called Gaddafi himself because he did not want to "disturb" him.
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 5 billion euros ($6.8 billion) a year.
The International Organization for Migration estimates that migrants from across Africa account for about 10 per cent of Libya's six million population, although only a minority of those attempt to travel on to Europe to find work.
The European Commission said in October it would spend 50 million euros to help Libya tackle illegal migration and protect migrants' rights.
Meanwhile, Ali al-Essawi, Libya's ambassador to India resigned in protest at his government's violent crackdown on demonstrators calling for the ouster of Gaddafi, the British Broadcasting Corporation (BBC) reported on Monday.
Essawi also accused the government of deploying foreign mercenaries against the protesters.
Earlier on Monday, Hussein Sadiq al Musrati, a senior Libyan diplomat posted in China also resigned and called on the army to intervene in the bloody uprising against Gaddafii.
The diplomat stepped down in an on-air interview with Al-Jazeera and "called on all diplomatic staff to resign".