Rescuers work at the site of the explosions in the northern China's port city of Tianjin, on August 14, 2015
China's stone-walling after a huge industrial explosion in Tianjin has generated fear and suspicion among citizens shocked by the apocalyptic images and sceptical towards authorities notorious for their lack of transparency.
Dramatic footage and pictures flashed across social media after the blasts at a hazardous goods storage facility, soon giving way to fears that dangerous chemicals could cast a toxic cloud over one of China's biggest cities.
Wrong-footed officials and state media are failing to offer an authoritative narrative to calm their fears, observers say.
The government admits it does not know the contents of the warehouse's chemical stockpile -- and attempts to reassure the city's residents that they are safe and the air is clean are viewed with suspicion.
"They've certainly been beaten to it," said Nicholas Dynon, who researches Chinese media and propaganda at Macquarie University in Sydney.
"The news got out faster than they could have prevented it from getting out," he told AFP.
But true to form, China's Communist Party and state-controlled media apparatus rebounded quickly to follow a familiar script honed in dealing with a host of prior disasters.
Those include a massive earthquake in Sichuan in 2008, a fatal high-speed train wreck in Wenzhou in 2011, an explosion last year at a car parts factory in eastern China, a deadly stampede in Shanghai on New Year's Eve and a cruise ship disaster on the Yangtze River in June -- among others.
"They have used long-standing procedures," said Willy Lam, a Chinese politics expert at the City University of Hong Kong.
"They have not been very transparent, they don't want to disclose all the information at one go and they are trying to calm down the people," he added.
"The scale of the disaster has not been disclosed at this stage."
In August last year an explosion at a car parts factory in Kunshan, near Shanghai, was initially said to have left more than 70 people dead. But at the end of December, the government suddenly announced that the toll had ballooned to 146.
Chinese newspapers and television have carried extensive coverage of the Tianjin explosions, which killed more than 50 people and injured hundreds, focussing on efforts of firefighters, rescue workers and medical personnel.
But officials appear uncomfortable providing nuanced, detailed and sensitive information related to the cause of the explosions and -- crucially -- the nature of the chemicals blasted into the sky and their impact on human health and the environment.
After addressing a press conference, the head of the Tianjin environment protection bureau attempted to leave his seat but reporters started shouting questions.
He appeared unprepared for the scrutiny, casting unsure glances at nearby officials before live TV coverage abruptly cut away.
Efforts to research the warehouse operator were obstructed when an official local company database displayed a message that "due to the dangerous goods warehouse explosion accident", its service had been "suspended temporarily".
- 'Give the public the truth' -
The Global Times newspaper, which has close ties to the ruling party, said in an editorial that information on the impact of the disaster should be provided, but called for patience on the part of journalists and the public.
Media should provide as many facts as possible "based on information offered by the official authorities, and with independent discoveries from the media", it said in an editorial.
But it warned that anyone questioning the rescue operation "should then seriously reflect on their constructiveness".
Some comments posted on Chinese social media calling for transparency -- or questioning the official toll -- were taken down by censors.
"Hope that the government will respect the facts, and give the public the truth," Yi Se, a user of Sina Weibo, wrote, though her entry had been removed on Friday, according to software created by University of Hong Kong researchers to identify posts censored online.
Another censored post was from Zhanlue Bingwang, who has more than 30,000 followers on Weibo. "Are all the people in this world fools?" he asked. "Watching the video of such a large explosion and there were only 50 people who died?"
Tianjin ranks among China's most advanced cities, and Dynon said the accident was likely to sow popular fears that "the rest of urban China is potentially one big tinderbox".
"The blast zone of the explosion -- as big as it was -- is nothing compared to the psychological impact zone for the hundreds of millions of people living in China's cities," he said.
"This no doubt informs the authorities' perceived need to control media coverage of the incident.But their efforts were self-defeating, he added. "It is this attempt to control -- and the vacuum of timely, meaningful reporting that has resulted -- that has done nothing to cushion this impact."