Multiple blasts shook the northeastern Chinese city of Tianjin late on Wednesday. State media has reported that over 300 people have been injured.
State news agency Xinhua reported that the fire had been brought under control, but that contact had been lost with two firefighters.
The blast had erupted from a shipment of explosives in a key industrial zone in Binhai New Area at about 11:30 pm local time (3:30 pm GMT), state broadcaster China Central Television said. The initial blast set off a chain of explosions in nearby industrial sites.
Images released by state media showed evacuated people running in the streets.
The blast wave shattered windows in some residential areas, witnesses say.