The International Criminal Court (ICC) prosecutor says she has suspended her investigation into war crimes in Sudan's Darfur region because of a lack of action by the UN.
Fatou Bensouda said there needed to be "a dramatic shift" in the UN Security Council's approach.
The Hague-based court indicted Sudanese President Omar al-Bashir in 2009 for alleged war crimes.
But he remains at large and has refused to recognise the court's authority.
Other Sudanese officials have been charged by the ICC, but none has been arrested.
Darfur has been in conflict since 2003 when rebels took up arms.
"It is becoming increasingly difficult for me to appear before you and purport to be updating you when all I am doing is repeating the same things I have said over and over again," Ms Bensouda told the Security Council.
"Given this council's lack of foresight on what should happen in Darfur, I am left with no choice but to hibernate investigative activities in Darfur as I shift resources to other urgent cases."
Analysts say action by the Security Council is unlikely because China - which wields a veto - has traditionally supported Sudan.
"We find ourselves in a stalemate that can only embolden perpetrators," Ms Bensouda said.
"What is needed is a dramatic shift in this council's approach to arresting Darfur suspects."
Last month, Sudan asked the UN-African Union force in Darfur (Unamid) to close its human rights office in the capital, Khartoum.
The move came amid tensions over the mission's attempt to investigate claims of mass rape by Sudanese troops in the Darfuri village of Tabit.
Ms Bensouda told the UN that the allegations should "shock this council into action".
However, Sudan has said it carried out its own investigation and had found no proof that anyone was raped.