Libya in 'crimes against humanity'
Prosecutors have identified at least seven incidents of demonstrators being shot in the early days of the Libyan uprising which could constitute crimes against humanity.
The chief prosecutor of the International Criminal Court, Luis Moreno Ocampo, said he aims to report on his investigation to the United Nations Security Council on May 4, before submitting a case to the court's judges.
But Mr Moreno Ocampo acknowledged the evidence may not be available to get dictator Muammar Gaddafi's name on to the charge sheet, and prosecutors will face a "challenge" to ensure suspects are detained and delivered to the court.
He told BBC Radio 4's Today programme: "We are collecting evidence, focusing on the first 12 days, which is a clear-cut situation where there were unarmed civilians in demonstrations. We are confirming that they were shot. We have evidence that they were shot.
"The issue for us now is to find who shot them and who ordered the shooting.
"We are identifying at least seven incidents which could constitute crimes against humanity and we are trying to get evidence of that and of who made the decisions and who did the shooting."
It will be for the judge to determine whether the incidents represent the kind of widespread, systematic attacks on civilians which amount to crimes against humanity under international law, he said.
Mr Moreno Ocampo said it is not clear how Libya would respond to any charges, as it previously signed up to a Security Council request for Sudan to co-operate with the ICC.
"We will see what Mr Gaddafi does, but I am not sure if he will be the person charged," he said. "I can't tell you that now.
"The next challenge after we send the case will be how to arrest the person."