At least five people were killed and 15 wounded in a car bomb attack in the eastern Libyan city of Derna, national news agency LANA reported.
The news agency, which is close to the internationally recognised government, added that it was a suicide attack.
"Fifteen people were also wounded... among them women and children," LANA reported, quoting local and medical sources in Derna.
The attack came after clashes between local militiamen controlling the city and Islamic State group fighters.
Libya descended into chaos after a revolt unseated longtime secular dictator Moamer Kadhafi in 2011.
It now has rival governments and parliaments, as well as powerful militias battling for influence and a share of its oil wealth.
The recognised government is based in the east of the country while the rival administration is in the capital Tripoli, which was overrun last year by a militia alliance, including Islamists.