Chinese officials have confirmed that a China Eastern Airlines plane carrying 133 people has crashed in Guangxi Province.
The Civil Aviation Administration of China said the plane was a Boeing 737, with 123 passengers and nine crew members on board.
It added that flight MU5735 took off from Kunming at 13:11 local time (05:11 GMT) and was heading to Guangxi.
It is not yet known the number of casualties and the cause of the crash, and it is feared that there are no survivors.
State media said the plane crashed in a mountainous area in Wuzhou Province, and the explosion caused a forest fire.
Rescue teams were deployed in the area. The Civil Aviation Authority said it had also sent some of its personnel to the scene.
Videos circulated widely on social media, apparently taken by local residents, show the wreckage of the plane scattered around the hills, and fire and smoke rising from the site of the accident. These videos were used by Chinese state media in their coverage of the accident.
China Eastern Airlines has yet to comment on the incident or respond to any inquiries, but it has changed its logo on its website to gray.
Flight tracking websites reported that the plane had been in the air for more than an hour and was approaching its destination.
According to data from flight tracking devices and software such as Flightradar24, the last information released regarding the flight was 14:22 local time, and showed that the plane was at an altitude of 3,225 feet.
China has had a good aviation safety record for more than a decade.
The last plane accident in the country was in August 2010, when a plane from Harbin district of Yichun crashed, killing 42 people.