The top U.N. official in Afghanistan on Wednesday condemned the deaths of three female international aid workers and their Afghan colleague after their vehicle was attacked. The vehicle, belonging to the U.S.-based International Rescue Committee (IRC), was traveling from Kabul to Logar when it was fired on by unknown gunmen Wednesday morning. “I condemn this cowardly attack in the strongest possible terms and urge the authorities to leave no stone unturned in the search for the perpetrators,” Kai Eide, the U.N. secretary-general's special representative to Afghanistan, said in a statement. “The IRC provides life-saving humanitarian assistance to those most affected by the conflict, and it is reprehensible that such selfless individuals working for the most vulnerable communities should be deliberately targeted in this way,” Eide said. Eide, who heads the U.N. Assistance Mission in Afghanistan (UNAMA), noted the “growing humanitarian challenge” in the country and urged all parties to recognize and respect the neutrality and independence of the humanitarian assistance being provided to the Afghan people. This year, Afghanistan has witnessed some of the worst violence since the overthrow of the Taliban regime six years ago.