Two contract workers attached to NATO's coalition forces in Afghanistan were killed in a suicide bombing Monday in Kabul, the coalition said in a statement. "Two International Security Assistance Force-contracted civilians died as the result of a vehicle-borne improvised explosive device attack in eastern Afghanistan today," the statement said. Haroon Zarghun, a spokesman for the militant Hezb-e-Islami, said the Taliban-aligned group took credit for the attack, saying it was carried out by a "martyrdom seeker" targeting a U.S. convoy, the Wall Street Journal reported. "He has been watching them since a week and was looking for an opportunity to target the convoy and not harm civilians," Zarghun said. "We only carry martyrdom-seeking attacks on foreigners. We don't conduct such attacks against Afghan police, army and civilians." The blast damaged a vehicle in the convoy, a civilian's car and blew out windows of houses, officials said. In keeping with its policy, the ISAF said it deferred casualty identification procedures to the appropriate national authorities.