Gunmen who came looking to steal satellite phones fatally shot a 39-year-old Sudanese relief worker in western Darfur, his Canadian-based aid agency said Tuesday. The killing comes as tensions are escalating in Darfur after an international court issued an arrest warrant for Sudan's president for war crimes here. In response, President Omar al-Bashir expelled 13 foreign aid agencies from Darfur, accusing them of cooperating with the court - raising fears of a backlash against humanitarian groups in the vast western Sudanese region. Adam Khater, who was the Fellowship for African Relief's Darfur director, was shot to death at his home on Monday night in the town of Kongo Haraza, near Sudan's border with Chad, said Mark Simmons, country director for the Ontario-based organization. Simmons said Khater's vehicle was ambushed Saturday night and he believed that attack was related to Monday's killing.