BEIJING -- U.S. Army investigators said on Monday they may have found the crash site of a CIA plane shot down over northeastern China nearly 50 years ago, but did not find the remains of two pilots who died in the crash.

A team from the U.S. Army Central Identification Laboratory in Hawaii located a "debris pattern" of wreckage in a forest in Jilin Province near where an elderly witness said the plane crashed about 50km (30 miles) from the North Korean border.

"We identified a relatively concise pattern of debris within about a 20 to 30 (square) meter area of concentrated small aircraft parts. I can't say if it's specific to that aircraft," said Franklin Damann, the team's anthropologist.

The investigators had also searched a larger area and did not find any other debris, he said.

"So, to me, I think that we have identified the area where the aircraft crashed," Damann added.

None of the aircraft pieces could be identified as belonging to the unmarked C-47, piloted by Robert C. Snoddy and Norman A. Schwartz on a failed mission to extract people on the ground on the night of November 29, 1952.

And the team did not find any evidence of the two pilots, despite the accounts of where their bodies were by a 78-year-old farmer who witnessed the crash and helped bury them.

"We did not find any remains on this investigation," Damann told a news conference.

Two other crew survived the plane crash and were imprisoned in China until the early 1970s.

The Jilin investigation was the first by a U.S. team looking into Cold War-era American servicemen missing in action in China. Similar teams have searched for the remains Americans lost in China during World War II, Reuters reported.

Its success hinged largely on the fading memories of the elderly farmer, the only known living Chinese witness to the crash.

The man had watched from his doorway that cold night as the plane circled once and then went down in the woods, said James Becker, an army major who led the investigation.

Six hours after the crash, the witness and four others, who have since died, found the plane and attempted to bury the two dead Americans in the frozen ground.

"Since he did go to the site, he could provide first-hand knowledge of the way the aircraft crashed," Becker said, adding the witness, who he did not name, also described the direction from which the plane came in.

"He did provide first-hand knowledge as to how the pilots were in the aircraft wreckage," he said.

Aaron Lehl, an analyst on the investigation team, said the two Americans who survived the crash had also been helpful, but did not give details.

The team would present photographs, a sketch of the crash site and other findings to headquarters in Hawaii to determine if more information was needed or if it should return to excavate the site, Becker said.

"This was an investigation. We do investigations.

We do excavations. The two are distinctly different," he said.

One member of the team estimated that "in the neighborhood of about 20 something" Americans were missing from the Cold War, but declined to estimate how many were in China.

Some 78,000 were still missing from World War II, he said.