Islamist fighters clashed with pro-government forces for the second consecutive day Sunday as they pressed an advance on a key oil region in eastern Libya, sources on both sides reported.
Separately, at least 17 Fajr Libya militiamen were killed in an air strike by pro-government forces near the Ras Jedir border crossing with Tunisia, a military source told AFP.
Fajr Libya, an anti-government coalition of Islamist militias, said its men were advancing on Al-Sidra oil terminal in Al-Hilal region, which is also home to the Ras Lanuf and Brega terminals.
A news agency linked to the group quoted Islamist commander Tareq Shanina as saying his men "advanced toward Al-Sidra" and were coming under air attack from pro-government forces.
Shanina said Fajr Libya fired anti-aircraft guns in response.
An official with a unit guarding oil installations said clashes were under way around Al-Sidra, Libya's largest oil terminal.
On Saturday, Fajr Libya launched a three-pronged attack to seize control of Al-Hilal but pro-government forces backed by air force jets and helicopters repelled the assault.
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The air raids were followed by clashes on the ground that tapered off in the evening only to resume again Sunday.
There were no immediate reports of casualties from Sunday's fighting there. On Saturday five government soldiers were wounded and Fajr Libya reported that two of its fighters had been killed.
The military source, who declined to be named, said Sunday's air raid near Ras Jedir was carried out by forces loyal to anti-Islamist ex-general Khalifa Haftar who is fighting to crush Islamists who control swathes of Libya.
More than three years after dictator Moamer Kadhafi was toppled and killed in a NATO-backed revolt, Libya is still awash with weapons and powerful militias, and has rival parliaments as well as governments.
Islamists have seized Tripoli and second city Benghazi in the east, and forces loyal to international recognised Prime Minister Abdullah al-Thani are fighting to regain control of them.
On Sunday, seven police stations closed five months ago during fighting between Islamists and Haftar's forces reopened in Benghazi, a spokesman for security forces told AFP.
First Lieutenant Tareq al-Kharraz said other facilities would be relocated from areas of Benghazi that are still under Islamist control to those where pro-government forces are deployed.