At least two people were killed on Sunday (26 November) and many injured after a powerful blast rocked the port city of Ningbo in eastern China's Zhejiang province, bringing down buildings. Cause of the blast was unknown, police said.

The explosion occurred at around 9am local time (1pm GMT), shattering windows of buildings located up to one kilometre from the blast site, South China Morning Post website reported. According to local media reports, the blast took place in an industrial area and residential buildings around were damaged.

More than 30 people were rushed to nearby hospitals amid the rescue operation, according to state media.

Local news portal run by the Ningbo government showed plumes of white smoke above the city. China Central Television (CCTV) reported that the blast was not a gas explosion, but did not elaborate further.

Police on social media said that an investigation was underway to determine the cause of the explosion. They told Reuters that the area where the blast took place had been marked for demolition in the recent past.

Video footage on local media channels reportedly showed rescuers carrying people away from the affected area and the piles of debris.

An eye witness, identified only by his last name Feng, told the South China Morning Post that he is the owner of Dazhong Restaurant, located about 1km south of the explosion site. Glass windows of his eatery shattered due to the explosion, he said and added that the blast took place inside a roadside house that was used for commercial purposes and was earmarked for demolition.

Another restaurant owner in the area, identified as Dong, told the website on phone that his shop was about 500 metres away from the explosion site and all the windows facing the scene of the blast were shattered. "Many police cars, ambulances and fire trucks all arriving," Dong added.