At least two people were killed when a powerful explosion in a Chinese city south of Shanghai brought down buildings in a neighbourhood marked for demolition on Sunday.
The explosion struck at around 8.50am in the Jiangbei district of the port city of Ningbo in Zhejiang province, China Central Television (CCTV), the state broadcaster, reported.
Police said the cause of the blast was still uncertain but was being investigated.
A "huge tremor" was felt in the vicinity when it hit, tweeted CGTN, a network operated by CCTV.
The force of the explosion destroyed the roofs of two buildings at the site of the blast, which CCTV said were already structurally unsound.
It also shattered windows and punched holes in the walls of some residential and commercial properties as far as a kilometre away.
Images from CCTV also showed a few flattened cars and a low-rise building with a collapsed wall.
The broadcaster said two people were killed, while 16 were slightly wounded and two were in serious condition.
It added that the blast was not a gas explosion, as the gas pipelines beneath the ground were no longer active, citing the operator of the pipelines.
According to the local Zhejiang Daily newspaper, the buildings that collapsed had already been cleared of people. Police said the area had been marked for demolition.
The official People's Daily newspaper said there were no residents at the site of the explosion, though there might have been rubbish collectors at work when the blast occurred.
Earlier in the day, the official agency Xinhua news agency said the blast had happened at a factory.
Rescue work and an investigation into the cause were under way, local police said on Weibo, the Chinese social media platform similar to Twitter.
Blasts and other accidents are common in China due to patchy enforcement of safety rules, although the government has pledged to improve checks to try to stamp out such incidents.
In 2015, giant blasts killed at least 165 people in the northern port city of Tianjin, causing over US$1 billion in damage and sparking widespread anger over a perceived lack of transparency by officials about the accident's causes and its environmental impact.
A government inquiry into the Tianjin accident released in February last year recommended that 123 people be punished.
The official who was mayor at the time of the accident was sentenced to 12 years in prison for graft in September.
Huang Xingguo, 62, had also headed the disaster response committee.
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