The United Nations human rights office called on Sudan on Friday to cooperate with the International Criminal Court (ICC), which issued an arrest warrant for deposed President Omar al-Bashir for alleged war crimes nearly 15 years ago.

“We do encourage the authorities in Sudan to fully cooperate with the ICC, there is a Security Council resolution as far back as 2005 calling on the government of Sudan to fully cooperate with and provide assistance,” UN human rights spokesperson Ravina Shamdasani told a Geneva news briefing.

Earlier, U.N. human rights chief Michelle Bachelet said Sudanese authorities should release people held for peacefully protesting and investigate the use of force against demonstrations since December.

Meanwhile, Sudan’s ruling military council expects a transition period it announced on Thursday to be two years at most, and said it can be as short as one month if it is managed “without chaos”, said the head of the council’s political committee.

The head of the transitional military council, Defence Minister Mohammed Ahmed Awad Ibn Auf, said on Thursday when announcing the overthrow of Omar al-Bashir that the council would lead a two-year transition before holding elections.