A suicide car bombing has killed at least 10 members of forces allied to Libya's internationally backed government west of the coastal city of Sirte, according to hospital sources.
Seven others were wounded in Thursday's attack which was blamed on the Islamic State of Iraq and the Levant (ISIL, also known as ISIS).
"Ten dead and seven wounded were brought in ... after a suicide attack carried out by Daesh [an Arabic name for ISIL] in Abu Grein," 130km west of Sirte, a source at the central hospital in Misrata told the AFP news agency.
The figures were also confirmed by hospital spokesman Abdel-Aziz Essa, who told the Associated Press that the attack took place in the early hours of Thursday.
The UN-backed government forces have recently launched an offensive from the western city of Misrata against ISIL fighters.
READ MORE: How serious is the ISIL threat in Libya?
The fighting in Sirte, the final ISIL stronghold in the oil-rich country, started in early May.
It is being led mostly by fighters from Misrata, which is aligned with the UN-brokered government based in the capital, Tripoli.
The government-allied fighters face increasing resistance from ISIL, which has retaliated with roadside bombs and suicide attacks.
Sirte, around 450km east of Tripoli, is strategically important because it links Libya's east and west.
Libya has been in turmoil since the 2011 revolt which toppled longtime leader Muammar Gaddafi, and ISIL has taken advantage of the chaos to seize territory along the sparsely populated central coast and expand in the country.