Four people were killed in Vietnam on Wednesday when an American-built helicopter crashed just minutes after it set off from the southern city of Ho Chi Minh, media reports said. The helicopter, which was once used in the Vietnam War, reportedly lost contact eight minutes after it took off from the Tan Son Nhat International Airport, Agence France-Presse (AFP) reported, citing officials.

The reason for the crash of the UH-1 helicopter, also known as Huey, is still being investigated. The chopper reportedly hit the ground at Pham Van Hai Commune of Binh Chanh District on Wednesday, Tuoi Tre, a state-run newspaper reported, citing Lt. Gen. Vo Van Tuan, deputy chief of the general staff of Vietnam People's Army. The chopper can carry a maximum of 14 people, including a four-member crew.

"All the four crew members onboard were killed. We are checking the reason for the crash," Tuan said, according to AFP.

Four soldiers, including a senior lieutenant colonel, were on board the helicopter, which was flying to the southern province of Tay Ninh, 62 miles from Ho Chi Minh, when it lost contact, according to Tuoi Tre. The names of the deceased have reportedly not been disclosed. 

The helicopter, which originally belonged to American forces, was seized by communist forces after the Vietnam War, which lasted until 1975, The Associated Press reported, citing Tuan. Vietnam’s military reportedly took control of about 50 American Hueys after the war and still uses many of them for military training, and search and rescue missions.

Last July, a Russian-made MI-171 military helicopter crashed near the capital of Hanoi during a parachute training program and killed 16 soldiers.