At least 13 rebels are reported to have been killed in Libya when a NATO plane enforcing a UN 'no-fly' zone fired on a convoy between Brega and Ajdabiya on Friday night.
They had reportedly fired an anti-aircraft gun into the air.
The rebels say a coalition plane then opened fire on the convoy, destroying five vehicles.
The reason for the gunfire is unclear but it may have been in celebration.
The BBC reports there is very little clarity surrounding the incident which is is thought to have happened between 11pm and midnight local time.
NATO said it was looking into the incident but that it was very difficult to verify details about what happened.
NATO said it regretted any loss of civilian life.