German Brig. Gen. Carsten Jacobson, a spokesman for the U.S.-led coalition, told reporters at a briefing Monday that troops have secured the crash site in Wardak province and nobody is being allowed in or out of the area while the investigation is ongoing.
Jacobson says the coalition still has not determined the exact cause of the crash.
It was deadliest single incident for U.S. forces in the decade-long war.
Several U.S. officials have said that insurgents apparently shot down the Chinook on Saturday as it rushed in to reinforce Army Rangers who had come under fire.