Rebel troops in Libya are calling on Nato to explain a "friendly fire" air strike on a column of rebel tanks that left at least four dead.
Gen Abdelfatah Yunis said he assumed the incident had been a mistake by Nato, but wanted a "rational and convincing explanation".Nato has said it is investigating the claims.
It is the third such incident in recent days involving international forces deployed to protect Libyan civilians.
"We are not questioning the intentions of Nato, because they should be here to help us and the civilians," Gen Yunis told a news conference in Benghazi on Thursday.
"But we would like to receive some answers regarding what happened today."
He added: "We would assume it was Nato by mistake, friendly fire."
But if speculation in some quarters that the attack was carried out by Col Muammar Gadaffi's forces turned out to be true then it would be "a bigger mistake", he added.
"We're under a no-fly zone that should be protecting us from Gadaffi's aircraft," he said.