The U.N. humanitarian chief urgently called on world leaders Friday to vastly increase the number of troops in Sudan's Darfur region to protect unarmed civilians and humanitarian workers facing a wave of murder, rape and looting. Jan Egeland depicted a crisis in which the number of people needing lifesaving assistance could jump from two million to four million if immediate action isn't taken. Addressing a news conference, Egeland backed a recent U.N. report which found that war crimes and crimes against humanity had taken place in Darfur and called for the perpetrators to be sent to the International Criminal Court. "The armed men in militias are getting away with murder of women and children and it is still happening. Those who direct the militias, these forces are also getting away with murder. It's impunity what we have seen taking place in Darfur," he said. "There should be sanctions. Which ones and against whom? Not for me to decide. There should be more robust action." Egeland said the need for more African Union troops is urgent. While there are 9,000 aid workers in the western Darfur region, there are only about 1,850 soldiers from the African Union, he said.