At least 44 people are now known to have died, and more than 500 injured, following two major explosions in China’s northern port city of Tianjin.
Twelve firefighters were among the dead, China’s official Xinhua news agency said as it reported a doubling of the death toll.
Two blasts happened in a warehouse storing “dangerous and chemical goods” in the port area of the city.
The blasts caused a huge fireball that could be seen from space.
Buildings within a 2km radius (1.5 miles) had windows blown out, office blocks were destroyed and hundreds of cars burnt-out.
Images on Chinese media showed local residents and workers fleeing their homes, some of them covered in blood from broken glass and flying debris.
As of 12:00 local time (04:00 GMT), 44 people had died and a total of 520 people had been hospitalised, including 66 in a critical condition, Xinhua reported.
The first explosion occurred at about 23:30 local time (15:30 GMT) on Wednesday, followed seconds later by another, more powerful blast and a series of smaller explosions. The impact could be felt several kilometres away.
The China Earthquake Networks Centre said the magnitude of the first explosion was the equivalent of detonating three tonnes of TNT, while the second was the equivalent of 21 tonnes.
State broadcaster China Central Television (CCTV) said a shipment of explosives had detonated but this has not been confirmed.
Senior managers of Ruihai Logistics, which owns the warehouse where the explosion happened, are being questioned by authorities, state media report.
One witness, named only as Ms Yang, told local media she was out shopping when “suddenly from behind there was a big fireball and explosion”.
“At the time of the explosion the ground was shaking fiercely, nearby cars and buildings were shaking, glass from a few buildings all broke and everyone started to run,” she said.
At the scene: John Sudworth, BBC News, Tianjin
The apartment complex closest to the explosion has eight rows of high-rise tower blocks.
In every one of them, almost every window has been blown out. On the ground outside are the signs of the many families who have fled from their beds in a hurry – a woman’s shoe, children’s toys, mangled bicycles.
There would have been many injured here. Inside the homes, furniture has been picked up as if by a whirlwind and interior doors lie at angles, ripped off their hinges.
“It was like what we were told a nuclear bomb would be like,” truck driver Zhao Zhencheng told the Associated Press. “I’ve never even thought I’d see such a thing. It was terrifying, but also beautiful.”
Another witness, Canadian teacher Monica Andrews, told how she woke in panic after what she thought was an earthquake.
“I… looked out the window and the sky was red. I just watched a second explosion go off and [it was] just pure chaos, everyone leaving their apartment buildings thinking it’s an earthquake, cars trying to leave the complex. It was crazy,” she told the BBC.
China National Radio said cracks were visible in buildings near the site of the blast.
Several tower blocks near the port area are without power, CCTV added.
Tianjin, home to some 15 million people, is a major port and industrial area to the south-east of the Chinese capital, Beijing.