China Eastern plane crash rescuers find no survivors
Rescuers have found no survivors so far from a jet carrying 132 people which crashed in hills in southern China.
Crash investigators also had no information on why China Eastern flight MU5735 plummeted out of the sky on Monday.
Recovery work at the site of the Boeing 737-800 crash in Guangxi province is being hampered by difficult terrain.
There has been an outpouring of grief in China, where families of passengers and crew are waiting for news.
Hundreds of responders have been scouring the steeply forested slopes in Wuzhou where debris from the plane was strewn after it broke apart and set fire to the hillside.
There had been no official word on casualties until China's Civil Aviation Administration held its news briefing, some 36 hours after the disaster.
"Up to now, search and rescue work has not found any survivors," Zhu Tao, aviation safety office director at the CAA, told reporters. "Given the information currently available, we still do not have a clear assessment of the cause for the crash."
Air controllers had repeatedly called the aircraft during its descent but had received no response, he added.
Rescuers have so far found parts of the 737's burnt wreckage. State broadcasters showed images of the charred remains of letters, bags, wallets and identity cards belonging to those on board.
Meanwhile, the families and friends of the 123 passengers and nine crew have gathered at each end of the flight - with relatives visiting China Eastern's offices in Yunnan province and waiting at Guangzhou International Airport.
The China Eastern Airlines flight from Kunming, the capital of Yunnan, had been due to land in Guangzhou on Monday afternoon.
China Eastern has grounded all its Boeing 737-800s and set up a hotline for people seeking information on those on board.
Authorities have yet to identify passengers and crew members, but some relatives have spoken to local media or shared their grief online.
One woman reported the loss of her newly-wed husband on her WeChat account. Her earlier posts included videos of the couple's holiday trips.
Other passengers included a group of six people, one of them a teenager, who were on their way to Guangzhou to attend a funeral, a local newspaper reported.
Another woman interviewed said her sister and close friends were part of that group, adding that she had also been booked on the flight, but ended up switching to an earlier plane.
"I feel very anguished," she told Jiemian News.
Reuters quoted a man at the airport who said he was the colleague of a passenger named Mr Tan.
After confirming that Mr Tan was on board, he had to break the news to Mr Tan's family. "They were sobbing. His mother couldn't believe this had happened," he told the news agency. "Her boy was only 29 years old."
He added that arrangements were being made by the airline to bring families to the crash site in Wuzhou.
Pictures show distraught families waiting in a cordoned-off area at Guangzhou airport, being assisted by airline staff.
One unverified clip circulating widely on Chinese social media shows a man slumped in his seat crying and lamenting the loss of his three children who were on the flight.
This accident took place in China and involved a Chinese airline. As such, the investigation will be led by the country's civil aviation administration.
But under international standards, the US will also be entitled to appoint an accredited representative because the Boeing 737 was designed and built in the US. The National Transportation Safety Board has already appointed a senior air safety investigator to fulfil this role.
Representatives from Boeing itself, the engine maker CFM International and the US aviation regulator, the Federal Aviation Administration, will serve as technical advisers.
The priority now will be to gather evidence from the crash site and search for the "black boxes", the flight data recorder and cockpit voice recorder.
If they can be found, and the data they contain is readable, then the immediate cause of the crash could become apparent quite quickly. But the investigation as a whole will take time.
Flight MU5735 had been in the air for more than an hour and was nearing its destination when it suddenly plummeted from its cruising height.
Chinese state TV outlets have broadcast footage which appears to show a jet in a near nosedive to the ground. The footage was captured by a car's dashcam. The BBC has not yet been able to verify the clip.
Flight tracker data showed the Boeing 737-800 jet dropped thousands of metres in under three minutes.
According to FlightRadar24, the plane was cruising at 29,100ft (about 9,000m), but two minutes and 15 seconds later it was recorded at 9,075ft. The last sourced information on the flight showed it ended at 14:22 local time, at an altitude of 3,225ft.
Aviation experts say the Boeing 737-800 model has a strong safety record, with thousands in service around the world. The aircraft that crashed was less than seven years old.
Investigators are expected to look at several possible causes - including deliberate action, pilot error, or technical issues such as a structural failure or mid-air collision.