CHENGDU, Nov. 11 (Xinhua) -- Chinese honor guards walked forward, carrying a box containing human remains. U.S. honor guards stepped up to receive it and carefully placed an American national flag over the box.

The box held eight bone fragments recovered from a glacier more than 5,000 meters above sea level. The remains, believed to belong to U.S. airmen who went missing along the Hump Route during World War II (WWII), had lain in the mountains for more than 80 years.

At the handover ceremony in Chengdu, southwest China's Sichuan Province, on Tuesday, He Jiang, director of the Chinese People's Liberation Army Archives, and U.S. Navy Captain Colin Alexander Eliot, a forensic expert with the Defense POW/MIA Accounting Agency (DPAA), signed a document confirming the transfer, witnessed by Chinese and American representatives.

The remains were recovered in areas along the Hump Route, which was established after Japanese forces occupied Myanmar in 1942, cutting off the Yunnan-Myanmar road, China's last major overland supply link to the outside world.

Stretching from the state of Assam in northeastern India to Kunming in southwest China, the air corridor across the Himalayas became a vital lifeline for Allied supplies supporting China's resistance against Japanese aggression from 1942 to 1945.

The route crossed snow-covered mountains, deep gorges, glaciers and tropical forests. Violent air currents, low air pressure, hail and freezing conditions posed constant risks to aircraft flying through the region. It became known as the "death route."

More than 1,000 Chinese and American aircrew members lost their lives along the route. With the high mountains and glaciers making searches exceptionally difficult, many of their remains have never been recovered.

The fragments handed over on Tuesday were found by a search team organized by Jianchuan Museum, a privately run museum in Sichuan, during expeditions to the glaciers of Nyingchi in southwest China's Xizang Autonomous Region.

The searchers trekked through primeval forests and waded across rushing rivers, taking care to avoid bears in the mountains and deadly hazards on the glaciers. After repeated searches, they finally located the remains.

China and the United States have cooperated in searching for American military personnel missing during WWII since the 1970s. Both Chinese authorities and civilian groups have contributed to those efforts.

An official with the general office of the Central Military Commission, who attended the ceremony, said the joint efforts to recover the remains of missing U.S. servicemen were a testament to the two countries' history of fighting side by side against Japanese fascism during WWII.

China has long supported the search on humanitarian grounds and is willing to continue practical cooperation with the United States in this field, the official said, adding that such efforts could contribute positively to building a constructive China-U.S. relationship of strategic stability.

"These remains bear witness to the war against fascism and carry the history of the Chinese and American peoples fighting aggression together," said Fan Jianchuan, curator of Jianchuan Museum. "They also remind us to strengthen cooperation and make new contributions to world peace."

Addressing the ceremony, Eliot spoke of the shared wartime history that the remains represent.

"The remains before us represent a defining historical moment when Americans, compelled by duty to defend against aggression, stood shoulder-to-shoulder with the people of China to fight that very same threat," he said.

Following the ceremony, Chinese and U.S. representatives visited the Hall of the Heroes of the Flying Tigers, which commemorates the Flying Tigers and other American servicemen who assisted China during WWII.

Through wartime artifacts and other displays, the exhibition documents the history of Chinese and American cooperation against Japanese aggression. It has received more than 10 million visitors since opening over two decades ago.

The airmen's identities have yet to be established. After the remains reach the United States, the DPAA will conduct DNA testing, examine historical evidence, and compare military records. Families will be notified only after identification is confirmed.