A US State Department spokesperson said his government is investigating if alleged government-backed militias are responsible for carnage in the oil-rich African country.

"It's an idea under active consideration. We are reviewing available information to determine which specific individuals could be designated as responsible," Adam Ereli told reporters. 

The US has a range of sanctions against Sudan already in place, but this would mark the first time it has targeted individuals.

The US has accused the Sudanese government of "ethnic cleansing" in Darfur while the UN has warned of hundreds of thousands of lives at risk because rains and government aid restrictions could stop sufficient relief reaching those affected by the conflict. 

Fighting in Darfur has driven more than one million people from their homes to other parts of Sudan and forced more than 150,000 to flee to neighboring Chad.

About two million in the region need outside aid, according to UN figures. 

Rebels launched a revolt in Darfur last year, accusing the government of neglect and of arming Arab units known as Janjaweed militias, who allegedly loot and burn ethnic African villages.

Khartoum has persistently denied the charges.