Mud-stained wallets, bank cards, official identity cards. Some of the personal effects of 132 lives presumed lost were lined up by rescue workers scouring a remote mountainside Tuesday for the wreckage of a China Eastern plane that one day earlier inexplicably fell from the sky and burst into a huge fireball.

No survivors have been found among the 123 passengers and 9 crew members. Video clips posted by China's state media show small pieces of the plane scattered over a wide forested area, some in green fields, others in burnt-out patches with raw earth exposed after fires burned in the trees.

Each piece of debris has a number next to it, the larger ones marked off by police tape.

As family members gathered at the destination and departure airports, what caused the Boeing 737-800 to drop out of the sky shortly before it would have begun its descent to the southern Chinese metropolis of Guangzhou remained a mystery.

The search for the black boxes, which hold the flight data and cockpit voice recorders essential to crash investigations, would be difficult, the official Xinhua News Agency said, and involve drones and manual search.

The crash left a deep pit in the mountainside, Xinhua said, citing rescuers. Chen Weihao, who saw the falling plane while working on a farm, told the news agency that it hit a gap in the mountain where nobody lived.

“The plane looked to be in one piece when it nosedived. Within seconds, it crashed,” Chen said.

A base of operations was set up near the crash site with rescue vehicles, ambulances and an emergency power supply truck parked in the narrow space. Soldiers and rescue workers combed the charred crash site and surrounding heavily dense vegetation.

Security was stepped up an entrance to Molang, a village near the crash site. Police officers could be seen checking each vehicle entering the village at a checkpoint. Five people with swollen eyes walked out through the entrance, got into a car and left. Onlookers said they were relatives of the passengers.

The steepness of the slope made positioning of heavy equipment difficult, although with few large pieces of the aircraft apparently remaining, there appeared little need for their use.

The Boeing 737-800 crashed outside the city of Wuzhou in the Guangxi region while flying from Kunming in the southwestern province of Yunnan to the industrial center of Guangzhou, not far from Hong Kong on China's southeastern coast. It ignited a fire big enough to be seen on NASA satellite images and was extinguished by firefighters.

Relatives of the passengers gathered at both airports. People draped in pink blankets slumped in massage chairs could be seen in a traveler rest area in the basement of the one in Kunming. Airport workers brought bagged meals and wheeled in mattresses. A security guard blocked an AP journalist from entering, saying that “interviews aren’t being accepted.”

In Guangzhou, family members were escorted to a reception center staffed by employees wearing full protective gear to guard against the spread of the coronavirus.

At least five hotels with more than 700 rooms had been requisitioned in Wuzhou's Teng county for family members, Chinese media reported.

The nation's first fatal plane crash in more than a decade dominated China's news and social media. World leaders including Great Britain's Boris Johnson, India's Narendra Modi and Canada's Justin Trudeau posted their condolences on Twitter.

Boeing Chief Executive Dave Calhoun said in a message that the company was deeply saddened by the news and had offered the full support of its technical experts to assist in the investigation.

“The thoughts of all of us at Boeing are with the passengers and crew members ... as well as their families and loved ones,” he wrote in a message to Boeing employees.

China Eastern Flight 5735 was flying at 29,000 feet (8,840 meters) when it entered a steep, fast dive around 2:20 p.m., according to data from FlightRadar24.com.

The plane plunged to 7,400 feet before briefly regaining about 1,200 feet in altitude, then dove again. The plane stopped transmitting data 96 seconds after starting to dive.

China Eastern has grounded all of its 737-800s, China’s Transport Ministry said. Aviation experts said it is unusual to ground an entire fleet of planes unless there is evidence of a problem with the model.

The airline has more than 600 planes, and 109 are Boeing 737-800s. The grounding could potentially further disrupt domestic air travel already curtailed as China deals with its largest coronavirus outbreak since the initial peak in early 2020.

Boeing 737-800s have been flying since 1998 and have an excellent safety record, said Hassan Shahidi, president of the Aviation Safety Network, an arm of the Flight Safety Foundation.

It is an earlier model than the 737 Max, which was grounded worldwide for nearly two years after deadly crashes in 2018 and 2019.

The crash site is remote, accessible only by foot and motorcycle, in Guangxi, a semitropical region of mountains and rivers famed for some of China’s most spectacular scenery.

The region lies just east of the agricultural, mining and tourism center of Yunnan province, of which the capital is Kunming, a city of 8.5 million that is a hub for trade with Southeast Asia and the northern end of a high-speed railway to neighboring Laos that opened in December.

Guangzhou to the west is China’s traditional foreign trade capital, lying at the heart of export-driven manufacturing industries in the country’s southeast that supply the world’s smartphones, toys, furniture and other goods and is a hub for a growing Chinese auto industry.

Also known as Canton, the city of 18.5 million is home to the Canton Trade Fair, the world’s biggest annual trade show. The Auto City district on Guangzhou’s northern outskirts has one of China’s biggest state-owned automakers, GAC Group, as well as factories for joint ventures operated by Toyota and Nissan and smaller brands.

Before Monday, the last fatal crash of a Chinese airliner occurred in August 2010, when an Embraer ERJ 190-100 operated by Henan Airlines hit the ground short of the runway in the northeastern city of Yichun and caught fire. It carried 96 people and 44 of them died. Investigators blamed pilot error.

The CAAC and China Eastern both sent officials to the crash site. The U.S. Federal Aviation Administration, which certified the 737-800 in the 1990s, said it was ready to help if asked.

Headquartered in Shanghai, China Eastern is one of the country’s top three airlines, serving 248 domestic and foreign destinations.

The aircraft was delivered to the airliner from Boeing in June 2015 and had been flying for more than six years.

The twin-engine, single-aisle Boeing 737 in various versions has been flying for more than 50 years and is one of the world’s most popular planes for short- and medium-haul flights.