China Eastern Airlines confirmed the details and said it has activated emergency procedures, including an emergency hotline for family members.
Rescue efforts are underway at the scene of the crash, but there were no immediate details on the possible cause or the number of casualties.
China Eastern offered its condolences to those killed in the incident, without confirming any death toll.
“The cause of the plane crash is still under investigation. The company expresses its heartfelt condolences to the passengers and crew members who died in this plane crash,” the airline said. in a press release.
Boeing said in a statement: “Our thoughts are with the passengers and crew of China Eastern Airlines Flight MU 5735. We are working with our airline customer and stand ready to support them.”
The company added that it is in contact with the US National Transportation Safety Board and its technical experts are ready to help with the CAAC investigation.
Chinese President Xi Jinping instructed the country’s emergency services to “organize a search and rescue operation” and “identify the causes of the accident”, state media reported.
“After the accident, President Xi Jinping immediately issued instructions to trigger the emergency mechanism, organize search and rescue, and properly handle the aftermath,” state broadcaster CCTV said.
The plane lost contact with emergency services before “suddenly descending” around 2:19 p.m., Chinese government officials and state media reported Monday.
“A China Eastern aircraft (flight number MU5735) lost contact at 2:15 p.m….Rescue teams are on their way to Ground Zero and rescue operations are underway,” the disaster management department said. Guangxi emergencies in a statement.
The plane’s altitude fell from 8,869 meters (29,098 feet) to 1,333.5 meters (4,375 feet) within three minutes, the official China News Service reported, citing VariFlight, a Chinese technology company that provides data services for civil aviation.
Hours after the crash, CCTV reported that the airline was grounding all of its Boeing 737-800s and that the aircraft currently in the air would “not be performing any further flights after landing”.
CCTV also reported that rescue efforts could be hampered by bad weather and limited accessibility to the site.
Heavy rescue equipment could not reach the scene – which lacks electricity – as it is surrounded by mountains on three sides and accessible only by a narrow path, CCTV said, citing the Guangxi Wuzhou fire department.
Separately, the Guangxi Meteorological Bureau warned that the rescue effort could be hampered by an incoming cold front that will bring heavy rains and a drop in temperature in Tengxian County, where the crash site is located.
A witness describes the fall of a plane
In an interview with state media Beijing Youth Daily, an eyewitness described seeing a plane “fall directly from the sky in front of him around 2 p.m.”.
“The plane fell vertically from the sky. Although I was very far away, I could still see that it was a plane. The plane did not smoke during the fall. The fire broke out after it fell in the mountain, followed by a lot of smoking,” said the witness, who was only identified by his last name, Liu.
“My heart was pounding. I immediately informed friends of the situation, that this area was dangerous and should not be approached,” Liu continued.
In a separate interview with China News Service, a resident of Molang village in Tengxian county – close to the crash site – reported seeing “wings and pieces of the plane, as well as clothes hanging from the trees”.
The witness – whose name has not been released – told state media he drove his motorbike to the crash site after hearing ‘a huge explosion’ around 2.40pm to ‘see if he could help to the rescue”. The viewer added that the accident caused “about 10 acres of fire”, according to his visual estimates.
A video showing what appears to be a plane falling nose-first from the sky circulated widely on Chinese social media on Monday, before being picked up and released by state media.
Footage posted online and shared by state media outlet People’s Daily shows plumes of smoke billowing from a mountainous, forested area. Another clip shows what appears to be the wreckage of the plane on a muddy mountain path.
The colors of the Boeing and China Eastern Airlines websites were changed to black and white in China, as a mark of respect in response to the accident.
CNN’s Hannah Ritchie, Helen Regan, Lauren Said-Moorhouse and Pete Muntean contributed to this report.