Warplanes from Libya's internationally recognised government have hit positions of the Islamic State group pushing eastward from their stronghold in Sirte toward the oil hub of Ajdabiya, a senior officer said Tuesday.
ISIS, which already 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 militants control Sirte, Gaddafi's hometown 450 kilometres (280 miles) east of Tripoli and have been battling both government forces and Islamists in second city Benghazi, a further 550 kilometres 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.
The senior officer said warplanes Tuesday struck a "house in an industrial area south of Ajdabiya where militants 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 ISIS, which has reportedly murdered 37 people, mostly military personnel, there in recent weeks.
ISIS, 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, have having been driven out by rival forces.