The international community is accelerating efforts to help oust Colonel Gaddafi.
Calls for tougher measures against his regime were made at a meeting of the UN Human Rights Council in Geneva.
Hillary Clinton accused the Libyan leader of using “mercenaries and thugs” to suppress the uprising. She warned the world would not stand for repressive violence.
“It is time for Gaddafi to go. Now. Without further violence or delay,” she said. “The international community is speaking with one voice and our message is unmistakable. These violations of universal rights are unacceptable and will not be tolerated.”
The West continues to study military options, notably a no-fly zone over Libya, but for this, UN approval is crucial.
The International Criminal Court says attacks against civilians in Libya could amount to crimes against humanity. And military commanders could be held accountable for the actions of their troops.
ICC Prosecutor Luis Moreno-Ocampo said: “I would like to put on notice everyone in Libya – anyone who decides to attack civilians could be investigated and prosecuted and the commanders have peculiar responsibilities because the commanders are in charge of the army and they know whatever the troops do, they could be responsible.”
The court in the Hague hopes to complete a preliminary examination of the violence in Libya within days.