V an Williams, spokesman, Dover Air Force base's mortuary affairs operations, said the helicopter crash "was so horrific" that the remains of the servicemen could not be easily identified.

Over the next few days, they will be identified by the mortuary team through DNA, dental records and fingerprints, he said.

"The crash they were in was so horrific and the state of remains such that there was no easy way to see this was this person or this was that person," Williams said.

The bodies, he added, were loaded into the plane "all together" in the transportation cases, rather than in the usual single container for each service member.