The International Criminal Court has issued arrest warrants for a Sudanese minister and a militia leader suspected of war crimes in the Darfur region
Humanitarian Affairs Minister Ahmed Haroun and Janjaweed leader Ali Muhammad Ali Abd al-Rahman, also called Ali Kushayb, are wanted on 51 counts.
Sudan says the ICC has no jurisdiction to try Sudanese and that its own courts are capable of prosecuting suspects.
Some 200,000 people have died in the four-year Darfur conflict, says the UN.
Mr Haroun was a minister responsible for the Darfur portfolio in 2003 and 2004.
According to the ICC he was responsible for organising and funding the Arab militia known as the Janjaweed.
Ali Kushayb is accused of ordering the murder, torture and mass rape of innocent civilians during attacks on villages near Kodoom, Bindisi Mukjar and Arawala in west Darfur.
"We completed an investigation under very difficult circumstances, from outside Darfur, and without exposing any of our witnesses," ICC prosecutor Luis Moreno-Ocampo said in a statement, AFP news agency reports.
"We transformed their stories into evidence, and now the judges have confirmed the strength of that evidence."
He told the BBC the government had a legal duty to arrest the men, even though Sudan is not one of the 120 states that signed up to the creation of the ICC.
"It is not just about punishment - but also unveiling the truth. I have to be ready to prove my case beyond any doubt so I still have a lot of work to do," he said on the BBC's Focus on Africa programme.
In February, the two men were named by the ICC as suspects in a total of 51 counts of war crimes and crimes against humanity including the murder, rape, torture and persecution of civilians in Darfur.
Correspondents say the ICC moves have transformed a long-running disagreement with Khartoum into a head-on collision.
Mr Haroun has said the move against him was political and that he had a clear conscience.
Mr Kushayb is thought to already be in the custody of the Sudanese government for attacks committed in Darfur, but Mr Moreno-Ocampo has said his evidence relates to different incidents.
Sudan has said it is capable of trying alleged war criminals without any help from the ICC.
Sudan has complained that the ICC has not indicted any Darfur rebels who it says are also guilty of murderous attacks.
It rejects the ICC's jurisdiction over its nationals and says it will not allow anybody, including rebels, to be tried outside Sudan.
The BBC's Geraldine Coughlan in the Hague says in the light of the court's decision, Sudan, despite its rhetoric, is now obliged to co-operate in handing these first two named suspects over to the ICC.
More than 2m civilians have fled their homes in Darfur, with most now staying in insecure camps supported by humanitarian agencies, who complain of frequent harassment from the Sudanese authorities.
Sudanese war criminals