An International Criminal Court prosecutor on Thursday urged the arrest of two Sudanese officials wanted for atrocities in Darfur and said he was outraged that one of the wanted men continues to oversee humanitarian assistance in the region.

Prosecutor Luis Moreno-Ocampo told the UN Security Council that Ahmad Harun and Ali Kushayb must be arrested immediately.

And he said it was "unacceptable" that Harun remains in his government post.

"It is of particular concern to my office that an individual sought by the court for atrocities committed against the civilian population … is still today the minister of state for humanitarian affairs of the Sudan," said Moreno-Ocampo.

"This is the same man who, in 2003, at a public meeting, declared that in being appointed to the Darfur security desk, he had been 'given all the power and authority to kill or forgive whoever in Darfur for the sake of peace and security,'" Moreno-Ocampo said.

Harun and Kushayb are facing 51 counts of war crimes and crimes against humanity. The International Criminal Court issued warrants for their arrest on April 27.

"We count on every state to execute an arrest should either of these individuals enter their territory," the prosecutor said.

The two men are accused of systematically pursuing and attacking innocent civilians. 

Harun, the former minister of state for the interior and head of security in Darfur is accused of recruiting, funding and arming Arab militia known as the Janjaweed, to supplement Sudan's army.

The court was told that Harun incited the forces to commit murder, rape and other crimes against the civilian population. 

Kushayb was a militia and Janjaweed leader who played a key role in Harun's system, personally delivering arms and leading attacks against villages, the criminal court was told.

At least 200,000 people have been killed and about 2.5 million have had to flee their homes in the past 3½ years of fighting in the western part of Sudan.

The United Nations has described Darfur as the "worst humanitarian crisis" in the world.