At least 50 people have been killed after a truck bomb targeted a police training centre in the western Libyan city of Zliten, the BBC reports.
Media in Libya said the attack struck the al-Jahfal training camp.
The training centre had been a military base during the rule of ousted Libyan leader Muammar Gaddafi.
Libya has been hit by instability since his overthrow in 2011, and there is concern Islamic State (IS) militants are gaining a foothold there.
The Lana news agency, run by the internationally-recognised government, said at least 50 people were killed and 127 injured in the blast, which was reportedly heard 60km (40 miles) away in Misrata.
Urgent calls for blood donations are being made to Zliten residents, the agency said