Pentagon researchers are searching for the remains of more than 2,000 American pilots and crewmembers lost over Papua New Guinea during World War II, it is reported.

Recovery teams — made up of some 30 active-duty soldiers, forensic anthropologists, bomb experts and natives — are scouring the nation's rugged terrain considered to be among the most difficult in the world, the Boston Globe reported.

Researchers have already spotted airplane wrecks and are trying to match up remains found in the area to names of missing service members lost in battle. Armed with high-tech tools, they are capable of extracting DNA from shards of tooth or bone, the Globe reported.

But tracking down the physical evidence can be like putting together pieces of a highly complex puzzle.

Researchers say the remains have been degraded by a range of man-made and natural forces, from insects to bandits. In addition, it is possible that wounded pilots from downed planes could have wandered off, further complicating the search, the paper reported.

The expedition is part of a new initiative to find MIA's from past wars and conflicts lost for decades in inhospitable terrain or in countries closed off by hostile regimes.

Some 78,000 of the estimated 88,000 MIA's still listed are from World War II. The Pentagon told the Globe that 20,782 service members are missing from the South Pacific alone.

Click here to read the full Boston Globe report.