Western governments are planning air strikes against the Gaddafi regime in Libya, which has reasserted its rule after weeks of protest, say analysts.
The developments come after the United Nations Security Council voted 10 to 0 in support of the use of "all necessary measures", including the use of a no-fly zone, to protect civilians and rebel forces in Libya from the country's government.
British, French and US military aircraft are preparing to defend the Libyan rebel stronghold of Benghazi, according to media reports.
A senior UK government source has told the BBC that action could take longer, but would be within days of the vote.
The UN resolution rules out a foreign occupation force in any part of Libya.
British Foreign Secretary William Hague said the UK would "now respond" to the responsibility it placed on UN members.
Reuters says that resolution 1970 authorises a no-fly zone over Libya and allows "all necessary measures" to be taken "to protect civilians and civilian populated areas under threat of attack in (Libya), including Benghazi, while excluding an occupation force."