TAIPEI, Taiwan -- A China Eastern Airlines Boeing 737-800 plane carrying 132 people slammed into the mountains of the southern province of Guangxi on Monday, according to China's aviation authority.
Footage of the crash captured by a local mining company showed the plane nosediving sharply into the mountainside in what appeared to be an almost vertical drop. In its statement, the Civil Aviation Administration of China said the flight carrying 123 passengers and nine crew members had lost contact over the city of Wuzhou in Guangxi.
According to data from Flightradar24, the China Eastern Airlines flight was cruising at 29,100 feet when it began to lose altitude suddenly, descending to 9,075 feet in just over two minutes.
The last recorded altitude was 3,225 feet, which indicated a final rate of descent of as much as 31,000 feet per minute. The flight was in the air for 48 minutes, according to the site.
The plane in Monday's crash was a Boeing 737-800 model, according to FlightAware. The airline has now grounded all of its Boeing 737-800 planes, the state broadcaster CCTV reported.
Chinese President Xi Jinping said in a statement that he was "shocked" to learn of the incident, according to CCTV, which reported that he had given "important instructions" to fully activate emergency response operations and investigate the cause of the crash.
Authorities had not confirmed any casualties, but by the end of the day there had been no reports of survivors.
The plane, China Eastern Airlines Flight 5735, was flying from Kunming to Guangzhou and was meant to arrive around 3 p.m. Hundreds of flights from Kunming and Guangzhou have since been canceled.
If all passengers on board are confirmed dead, the crash will be China's deadliest since 1994, when a China Northwest Airlines flight -- a Soviet-built Tupolev Tu-154 -- crashed in Xian, killing 160 people after the plane broke up in the air because of an autopilot malfunction.
China Eastern Airlines confirmed Monday's crash and said it was opening a hotline for the family members of those on board. In a statement Monday evening, the airline expressed its "deep condolences to the passengers and crew members that have died."
Video of the plane falling steeply toward the mountainside posted online was verified by the Paper, a Shanghai-based outlet, as footage from a surveillance camera installed by a local mining company. An employee of Beichen Mining told the outlet they had been outside at the time of the crash and heard a short, loud explosion.
Videos published by the official People's Daily newspaper showed thick smoke above a forest and a charred clearing, with pieces of the plane scattered on the ground.
The plane's rapid descent began at the point when it would have been beginning to head to land, according to tracking data. Veteran crash investigator John Cox said that while an airliner might normally descend at 6,000 feet per minute, the 737 was plummeting at more than three times that rate.
"Something happened at that top of descent that is out of the norm," Cox said. "That steep an angle is very unusual and that's something that the investigators are going to have to look at."
Investigators will also look at the history of the plane and the crew, and experts said the recovery of the plane's black boxes will be a key next step.
While it's hard to draw conclusions yet about what happened, experts said the weather was good and the plane did not appear to have broken apart in flight.
The National Transportation Safety Board said it has appointed an investigator to serve as the American representative to the investigation. Representatives from Boeing, engine manufacturer General Electric and the Federal Aviation Administration will also advise the investigation, the board said.
In a statement, Boeing said it is in contact with the National Transportation Safety Board and prepared to assist in the China-led investigation, adding "we are working with our airline customer and are ready to support them."
Hundreds of firefighters and search-and-rescue teams were sent to the scene, according to local officials. Beijing Youth Daily, citing an official in Tengxian, said teams from surrounding areas had been dispatched.
The teams reached the crash site and put out the fire but had not yet identified the remains of any of the victims, according to Guangxi fire services.
Information for this article was contributed by Vic Chiang and Lori Aratani of The Washington Post.