A China Eastern Airlines Boeing 737-800 with 132 people on board crashed in mountains in southern China on a domestic flight today after a sudden descent from cruising altitude. Media said there were no signs of survivors.

The airline said it deeply mourned the passengers and crew, without specifying how many people had been killed. Boeing said it was ready to assist China Eastern and was in contact with US transportation safety regulators over the incident.

The plane was en route from the southwestern city of Kunming, capital of Yunnan province, to Guangzhou, capital of Guangdong, bordering Hong Kong, when it crashed.

China Eastern said the cause of the crash, in which the plane descended at 31,000 feet a minute according to flight-tracking website FlightRadar24, was under investigation.

The airline said it had provided a helpline for relatives of those on board and sent a working group to the site. There were no foreigners on the flight, Chinese state television reported, citing China Eastern.

Relatives, friends and colleagues of passengers gathered late this evening in a cordoned off area at the jet's destination, Guangzhou Baiyun International Airport.

One man surnamed Yan said that a colleague had been on the plane, and that he had notified the 29-year-old's mother.

"When she picked up the phone, she choked up," said Yan, adding that he had a "heavy heart" when he heard the news.

China Eastern staff were making arrangements for relatives who wished to travel to the crash site tomorrow, Yan said.

The aircraft, with 123 passengers and nine crew on board, lost contact over the city of Wuzhou, China's Civil Aviation Administration of China (CAAC) and the airline said.

The flight left Kunming at 1:11pm (5.11am Irish time), FlightRadar24 data showed, and had been due to land in Guangzhou at 3.05pm (7.05am Irish time).

The plane, which Flightradar24 said was six years old, had been cruising at 29,100 feet at 6.20am Irish time. Just over two minutes and 15 seconds later, data showed it had descended to 9,075 feet. Twenty seconds later, its last tracked altitude was 3,225 feet.

Media cited a rescue official as saying the plane had disintegrated and caused a fire destroying bamboo trees. The People's Daily quoted a provincial firefighting department official as saying there was no sign of life among the debris.

State media showed a piece of the plane on a scarred, earthen hillside.

Crashes during the cruise phase of flights are relatively rare, even though this period accounts for the majority of flight time.

Boeing said last year only 13% of fatal commercial accidents globally between 2011 and 2020 occurred during the cruise phase, whereas 28% occurred on final approach and 26% on landing.

"Usually the plane is on auto-pilot during cruise stage. So it is very hard to fathom what happened," said Li Xiaojin, a Chinese aviation expert.

Online weather data showed partly cloudy conditions with good visibility in Wuzhou at the time of the crash.

President Xi Jinping called for investigators to determine the cause of the crash as soon as possible, state broadcaster CCTV reported.

Boeing said in a statement that its thoughts were with the passengers and crew.

"Boeing is in contact with the US National Transportation Safety Board and our technical experts are prepared to assist with the investigation led by the Civil Aviation Administration of China," the company said.

A person familiar with the matter said that Boeing has cancelled a meeting of its senior executives scheduled for this week in Miami to focus on assisting the investigation and China Eastern Airlines.

China Eastern grounded its fleet of 737-800 planes after the crash, state media reported. China Eastern has 109 of the aircraft in its fleet, according to FlightRadar24.