Unidentified war planes may have carried out overnight air strikes on the Libyan capital Tripoli, according to local media.
Residents reported seeing jets fly over the city and hearing explosions.
The government said it did not have any “convincing indications to establish which side was behind this”.
The country has been by gripped by fighting between rival militias that spearheaded the 2011 uprising against long-time leader Muammar Gaddafi.
The violence has been centred around the international airport in Tripoli and in the eastern city of Benghazi.
On Monday, several Libyan TV channels said planes had targeted bases of militiamen from Misrata who have been battling brigades from the western Zintan region to gain control of Tripoli.
Reuters news agency quotes forces loyal to renegade General Khalifa Haftar as saying they were behind what they termed air strikes “on some militias’ locations belonging to Misrata militias”.
The group’s claim could not be independently verified.
General Haftar was loyal to Gaddafi before joining rebel groups to oust him in 2011.
Several hundred people are believed to have died in July and August in an upsurge of unrest.
Thousands have fled their homes to escape the violence.
More than three years after Gaddafi was overthrown and killed, Libya’s police and army remain weak in comparison with the militias who control large parts of the country.