The Islamic State group is pushing eastward from its Libyan stronghold toward an oil hub but the government is trying to prevent this with air strikes.
In Paris, French Prime Minister Manuel Valls said on Tuesday (local time) the situation in the North African country will be "the big issue in the coming months".
IS, which controls large swathes of territory in Iraq and Syria, has exploited the chaos that spread across Libya after veteran dictator Muammar Gaddafi was toppled and killed in a 2011 uprising.
The jihadists control the oil hub of Sirte, Gaddafi's hometown 450km east of Tripoli and have been battling both government forces and Islamists in second city Benghazi, a further 550km to the east.
They are now trying to expand their zone of influence to Ajdabiya, which lies between Sirte and Benghazi and is in the heart of one of the North African country's major oil-producing regions.
A senior officer said warplanes on Tuesday struck a "house in an industrial area south of Ajdabiya where jihadists were meeting".
The attack was part of a campaign aimed at preventing them from capturing the city, which is held by militias loyal to the recognised government.
Tuesday's strike was preceded by others last week, the officer said.
Last month, Foreign Minister Mohammed Dayri warned that Ajdabiya was at risk of becoming a "new fief" of IS, which has reportedly murdered 37 people, mostly military personnel, there in recent weeks.
IS, which has claimed several deadly attacks in Libya, as well as the murder of hostages, is also trying to retake the city of Derna, in the country's far-east.
In New York, UN experts agreed in a report issued on Tuesday that IS is struggling to expand its foothold in Libya with no more than 2000 to 3000 fighters in the country.