The civilian MI8 helicopter crashed into mountains near the southeastern Paktia province.
Colonel Tom Collins, a spokesman for the US-led multinational force in Afghanistan, said 12 bodies had been recovered from the site, which had been secured by foreign troops.
He said the cause of the crash was not known.
A Taliban spokesman claimed that the group had shot down the helicopter.
The helicopter was flying to Kabul from Khost carrying contractors working for a reconstruction company.
Two Dutch soldiers from the International Security Assistance Force were among the dead.