In Sirte, the last bastion of the Islamic State group in the North African country, yesterday's clashes killed 36 militiamen aligned with the newly-UN brokered government.
The militias, mainly from the western town of Misrata, have been leading an offensive since early May to take full control over Sirte.
At first, the militiamen rapidly advanced into the city but the push got bogged down in recent days amid a series of suicide bombings by IS.
IS fighters reportedly have hunkered down at the militant group's headquarters in Sirte, the sprawling Ouagadougou convention center that was built by late dictator Moammar Gadhafi.
Sirte was also Gadhafi's birthplace and the city he fled to during the 2011 civil war, when Libyan rebels backed by NATO bombings forced him out of the capital, Tripoli.
Meanwhile, the state LANA news agency said an explosion at a depot yesterday in the town of Garabuli, near Tripoli, followed clashes with militias and killed 29 civilians.
When the protesters stormed the militia's barracks, the depot exploded, the statement said. It said that the depot housed firecrackers, not ammunition.
Photographs posted on the page showed charred bodies covered in plastic sheets.
The UN envoy to Libya, Martin Kobler, said on his Twitter account he was "shocked and saddened by reported violence and lives lost in Garabuli tonight."
The high death toll illustrates the violence that has roiled Libya since Gadhafi's ouster and death in the 2011 uprising against his rule that turned into a civil war.
As Libya slid into chaos, hundreds of thousands of mostly African migrants flooded the country's coastline, attempting to cross to Europe.
