Tripoli - A truck bomb attack on a police training centre in Libya's western city of Zliten has killed and wounded dozens of people, local media reports said on Thursday.
A report from the LANA national news agency under the control of Libya's internationally recognised government said at least 15 people had been killed and 30 wounded.
A rival news agency loyal to authorities in Tripoli, who are in control of Zliten, said at least 50 people had been killed and 127 wounded.
There was no immediate claim of responsibility for the attack.
Libya has been beset by chaos since the 2011 overthrow of longtime dictator Moamer Kadhafi and the Islamic State group has been gaining increasing influence.
The UN envoy to Libya, Martin Kobler, said on Twitter that the blast was a suicide attack.
"I condemn in the strongest terms today's deadly suicide attack in Zliten, call on all Libyans to urgently unite in fight against terrorism," he wrote.
Libya has had rival administrations since August 2014, when an Islamist-backed militia alliance overran Tripoli, forcing the government to take refuge in the east.
The United Nations is pressing both sides to accept a power-sharing deal agreed in December.