Internet videos showed fireballs shooting into the sky and the U.S. Geological Survey registered the blasts late on Wednesday as seismic events.
“We wish to express our condolences to the Chinese people over the explosion in Tianjin”, State Department spokesman John Kirby said Thursday. Windows were blown out of high rise apartments and office buildings were destroyed.
Stunning photographs showed the huge area flattened by the explosion, and also revealed the legions of walking wounded being led away from the site.
It said 44 people, including 12 fire fighters, have been killed and 520 others injured in the explosions.
Twelve of the dead were among the 1,000 firefighters sent to tackle the blaze, while 36 more were reported missing.
A team of military chemical experts is testing for toxic gases at the scene and rescuers have been ordered to wear protective clothing, state media said.
The official Xinhua news agency has said several containers in the warehouse caught fire before the explosions.
The Binhai New Area in northern China, where the blasts killed more than 50 people and injured more than 700, is a giant logistics hub more than twice the size of Hong Kong.
APPHOTO XHG129: Smoke billows from the site of an explosion that reduced a parking lot filled with new cars to charred remains at a warehouse in northeastern China’s Tianjin municipality, Thursday, August 13, 2015.
Hu Xiaoliang, a truck driver who was near the center of the blasts, tells Beijing News, “I was sleeping under my truck when the first blast occurred”.
Tianjin, with a population of about 15 million, is about 120km east of Beijing on the Bohai Sea and is one of the country’s major ports.
The blasts originated at shipping containers owned by a logistics company authorized to handle hazardous material and struck a mostly nonresidential warehouse district.
The AP is reporting that the explosions through the Tianjin port have “disrupted the flow of cars, oil, iron ore and other items through the world’s 10th largest port”. The National quake Bureau said the first was equivalent to 3 tons of TNT, and the second to 21 tons – similar to a tactical nuclear weapon.
A huge fireball lit up the sky, and nearby buildings have collapsed.
An estimated 6,000 people will have to be resettled because of the destruction caused by the blasts, authorities said.
Dozens of police guarded the entrance of the TEDA hospital, a Reuters witness said.
Firemen rest after their rescue work.
Senior managers at the company have been detained and President Xi Jinping has demanded severe punishment for anyone found responsible for the explosions.
Some Deere employees are not being allowed to return to their homes located near the blast site.