A Sudanese militia leader wanted by the International Criminal Court (ICC) for alleged war crimes in Darfur is in custody, a minister has confirmed.

The ICC issued an arrest warrant for Ali Mohamed Ali Abdel-Rahman - known as Ali Kushayb - in February last year.

Sudanese Justice Minister Abdel Basit Sabderat said an investigation into alleged crimes committed by Ali Kushayb was now drawing to an end.

The ICC chief prosecutor also accuses Sudan's president of crimes in Darfur.

The government is lobbying hard for the UN Security Council to delay an ICC investigation into whether President Omar al-Bashir should be charged with war crimes.

The BBC's Amber Henshaw in the capital, Khartoum, says Sudan has refused to co-operate with the ICC case and is insisting on conducting its own investigations into crimes in Darfur.

An arrest warrant for government minister Ahmed Haroun was issued at the same time as that for Ali Kushayb - the minister has not been arrested.

A new chief prosecutor was appointed in August to investigate crimes committed in the Darfur region during the five-year conflict.

Legal experts say that Sudanese criminal law does not include charges of genocide, war crimes or crimes against humanity although the military law was revised last year.

The government has always denied reports that it had backed the Janjaweed militias accused of widespread atrocities against civilians in Darfur.

More than two million people have been forced from their homes and an estimated 300,000 have died since black African groups took up arms in 2003, complaining of discrimination by the Arab-dominated government in Khartoum.