Hundreds of panicked shoppers have frantically fled a skyscraper after it began to shake for seemingly no reason.
The SEG Plaza in the Chinese city of Shenzhen, which has a population of more than 12 million, began to sway on Tuesday afternoon.
The 73-storey skyscraper, which stands at about 350 metres and is the eighth tallest in the city, sparked panic as there was no immediate explanation for what caused the building to wobble, with no earthquakes recorded in the area at the time.
New York Times reporter Austin Ramzy, who is based in Hong Kong, said on Twitter people fled as the building "tilted on its foundations".
In a video on the social media site, hundreds are seen sprinting from the building while looking back up at it rocking behind them as they scramble.
"Just at noon, the 73-story SEG Electronics building in Huaqiang North, Shenzhen, suddenly shook, and there was no earthquake, for unknown reasons," someone who posted a video wrote.
"The people in the building and downstairs fled for their lives."
In another aerial video, a street is seen crawling with people evacuating the area.
Authorities are probing into what caused the building to wobble, China's Global Times newspaper reported.
China State Construction Engineering Corporation senior engineer Lu Jianxin said however it could be "sheer coincidence".
"Judging from what's published, this could be a sheer coincidence – resonance," the engineer said.
Shenzhen's housing and construction bureau said the structure was safe and no ground cracks were located, the newspaper added.
The bureau said the building's interior steel structure was also in a normal condition.
The building had vibrated for about an hour before it stopped.
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