The International Criminal Court has reported Sudan to the UN Security Council for refusing to arrest two suspected Darfur war criminals.
Former Minister Ahmed Haroun and militia leader Ali Muhammad Al Abd-Al-Rahman are both alleged to have been involved in attacks on civilians.
The ICC took the unprecedented move after the government refused to accept arrest warrants for the two men.
It comes one day before President Omar al-Bashir starts a new term in office.
A special adviser to the ICC prosecutor, Beatrice le Fraper, told the BBC that similar action might be taken in relation to President Bashir, who is also wanted by the ICC for alleged war crimes in Darfur under a warrant issued in March 2009.
"The arrest warrant will not disappear [on Thursday] when there is an inauguration of President al-Bashir," said Ms le Fraper.
"It's very important that all those who attend the inauguration remember that it is first and foremost the inauguration of a man who has been charged with the crime of extermination."
Mr Bashir, who strongly denies the charges and rejects the jurisdiction of the ICC, has refused to hand over the two alleged war criminals.
He is due to be sworn in as Sudan's head of state on Thursday, after winning last month's elections.
Ms le Fraper said it was the first time the ICC had formally asked the Security Council to take action against a member country for failing to implement arrest warrants against its citizens.
The prosecutor will appear before the United Nations on 11 June to explain that Sudan has refused to arrest the indicted men, the BBC's Africa editor Martin Plaut reports.
They are former Humanitarian Affairs Minister Ahmed Haroun - who allegedly recruited, funded and armed the Janjaweed militia - and Ali Muhammad Abd-Al-Rahman, one of the most senior militia leaders.
Ms le Fraper said the Security Council had asked Sudan to co-operate with the court two years ago, but that the government had refused.
The warrants list 51 counts of crimes against humanity and war crimes allegedly committed in the war-torn Darfur region.
The charges include murder, torture, mass rape and the forced displacement of entire villages.
Since the conflict in Darfur began in 2003, some 2.7 million people have fled their homes and the UN says about 300,000 more have died.