At least 34 pro-Libyan unity government forces were killed and 100 more injured in clashes with DAESH in the coastal city of Sirte on Tuesday. "Dozens" of DAESH militants have been killed within 24 hours, said the pro-government fighters.
The clashes took place as the forces aligned with the Tripoli-based Government of National Accord (GNA) prepared for a final assault on the DAESH stronghold.
It was one of the bloodiest days since forces loyal to the UN-backed GNA launched an offensive in May to retake the city from DAESH.
A statement by the GNA said Tuesday's fighting took place in several parts of Sirte, where DAESH is confined to pockets of the coastal city.
The GNA earlier announced their "intelligence network is in full swing in preparation for the decisive battle" against DAESH in the city, after repelling multiple counter-attacks.
DAESH had seized Sirte, the hometown of former Libyan leader Muammar Gaddafi, in June 2015.
Blast in ammunition store kills 29
In a separate incident, at least 29 civilians were killed in an explosion at an ammunition store in Garabulli, 50 kilometres from Libyan capital Tripoli on Tuesday, a municipal official said.
Armed residents stormed an arms depot after clashing with a militia from the western city of Misrata which owned the weapons store.
As they breached the store a "big explosion" occurred, said a security official who could not immediately explain what triggered the blast. "Maybe the militia had rigged the depot before they left," he said.
A medical official said at least 29 people were killed and dozens wounded.
"There are body parts" at the arms depot, he said, adding the toll could rise.
According to the official, the clashes pitting armed residents against militiamen from Misrata broke out after some of the militiamen robbed a grocery store.
Angered, the armed residents attacked them at dawn.
The attack sparked clashes that lasted all day, the security official said.
The militias from Misrata honed their battle skills during the 2011 revolt and are now on the frontlines of the battle for Sirte. They are among the best equipped, with an arsenal that includes MiG fighters and attack helicopters.