Fatou Bensouda, the chief prosecutor at the International Criminal Court, told the U.N. Security Council she was frustrated with the level of inaction regarding war crimes in Darfur.
She said in a 10-page report as many as 300,000 people were displaced from Darfur during the first five months of 2013 -- more than in the last two years combined.
She called on the Security Council "to act with courage and conviction by adopting appropriate measures within its mandate to ensure that Sudan fugitives are brought to justice sooner rather than later" in testimony Wednesday.
Human Rights Watch said witnesses to an April raid in the Um Dukhun region of Darfur put former militia leader and police commander Ali Kosheib at the scene of alleged crimes against humanity.
Kosheib is wanted by the ICC for war crimes committed in Darfur from 2003 to 2004. An arrest warrant was issued by the ICC in 2009 for Sudanese President Omar al-Bashir for war crimes and crimes against humanity in Darfur.
The ICC said it was still monitoring reports of indiscriminate attacks by the Sudanese Ministry of Defense "which could be part of the ongoing acts of genocide, crimes against humanity and war crimes, as well as alleged attacks on civilians by rebel movements."