Afghan intelligence officials say an American civilian engineer has been found murdered in Kabul.
Military sources identified the victim as James W. Coker. Western sources say Coker had gone missing before he was found dead.
On Monday, NATO said that a U.S. Department of Defense civilian employee had died in eastern Afghanistan, but gave no other details.
Despite tight security in the Afghan capital, insurgents have been able to carry out high-profile attacks in Kabul.
Also Tuesday, Afghan authorities recovered the bodies of two Germans who disappeared last month while hiking in northern Afghanistan. The bodies were discovered on Monday in a remote area near the Salang Pass in Parwan province.
Afghan security forces traveled by foot through the Hindu Kush mountains to retrieve the Germans' bodies on Tuesday. Initial reports indicated the two had been shot, but the cause of death remains unclear.
Afghan authorities handed the bodies over to U.S. troops.
German Foreign Minister Guido Westerwelle has confirmed that two bodies were found in Parwan but refused to give any other details until they have been identified.
No one has taken responsibility for kidnapping the Germans.
Separately, Afghan officials say a roadside bomb Tuesday killed a district governor and three of his bodyguards in the eastern province of Nangarhar.
Sherzad district chief Asel Ahmad Khogyani was killed when the blast hit his vehicle.
Some information for this report was provided by AP and Reuters.