A court in the Darfur region of western Sudan has convicted seven men accused of membership in an Arab militia at the center of a conflict that aid groups say is causing the world's worst humanitarian disaster.

The court in the South Darfur state capital of Nyala sentenced the men, accused of membership in the Janjaweed militia, to execution, crucifixion, cross-amputation, imprisonment or fines, according to a statement from the presiding judge, Mukhtar Ibrahim Adam.

Cross-amputation is the amputation of a hand and the opposite foot.

Local police said they had detained 100 Janjaweed militiamen and other outlaws, official sources said Thursday. The court in Nyala had previously sentenced 10 suspected Janjaweed members.

The international community has been pressing Sudan's government to disarm and crack down on the militiamen, whose campaign of rape, looting and pillage in black African villages has led to the displacement of more than 1 million people.

Members of the international community have expressed doubts that the men in government captivity are Janjaweed members.

"At best those being captured are opportunists who have profited from the outbreak of conflict to loot and pillage and at worst these men are petty criminals who are being scapegoated," said one source at an international organization working in Sudan. "I don't think the government has the ability to really take on the Janjaweed leaders."

Human rights groups say the Sudanese military and the Janjaweed have worked together to drive people from their homes, but the government says the militiamen are outlaws and must disband.

South Darfur's police commander, Osman Abdullah, told reporters in Nyala that his forces had captured the 100 Janjaweed and other outlaws in a number of recent clashes.

A senior military intelligence official said the government would find it difficult to take on influential tribal leaders involved in a conflict pitting ethnic Arabs against black Africans in Darfur, which is on the border with Chad.

"The tribe in Darfur is the law," he said. "The problem we are facing is that the tribal leaders here are the government."

More than 1 million Sudanese, like this refugee child near the Chad-Sudan border, have been displaced during a conflict with Arab militiamen.