The ICC, in a sweeping decision, dismissed or ruled as inadmissible efforts by authorities in Tripoli to prosecute Saif al-Islam, a son of former Libyan leader Moammar Gadhafi.
The interim government in Tripoli had refused an ICC request to hand him over so he can face domestic courts.
The younger Gadhafi was captured in November and is subject to an arrest warrant issued by the ICC.
The ICC said it had evidence civilians were attacked in their homes, demonstrators were fired on with live ammunition and snipers were used to kill people leaving mosques in Libya.
"The appeal of Libya against the decision of Pre-Trial Chamber I entitled 'Decision Regarding the Second Request by the Government of Libya for Postponement of the Surrender of Saif al-Islam Gadhafi' is dismissed as inadmissible," a court summary read.
ICC chief prosecutor Luis Moreno-Ocampo arrived in Tripoli to meet with interim officials, including Justice Minister Ali Ashore, reports Bloomberg News. He's said to be in the country to discuss Gadhafi's trial with interim leaders.