Astonishing footage is emerging of people at Shanghai’s international airport being coralled into a carpark building after a sudden decision to test thousands for the coronavirus.

Multiple videos posted to social media appear to show authorities at Shanghai Pudong International Airport trying to contain crowds after several cases of COVID-19 sparked the mass testing push.

According to Global Times, a state-run media outlet, reported the testing blitz came after several cargo handlers and their close contacts were diagnosed with the virus.

Some Twitter users claimed the entire airport had been locked down and up to 100,000 people were quarantined ahead of virus tests.

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On the video, authorities in hazmat suits can been seen herding the crows and barring the paths of others as they try to flee. Elsewhere, workers form long, orderly queues for testing.

Hundreds of flights were cancelled after staff in the airport’s two main zones were told they had to be tested. Elsewhere, roads leading to the airport jammed up with traffic.

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Mainland China reported 17 new COVID-19 cases on Sunday. They included three from local transmission and nine originating overseas, according to the country’s National Health Commission.

Two of the local transmissions were in Inner Mongolia and one in Shanghai.

Inner Mongolia’s health authority said on Saturday it had confirmed two new coronavirus cases in Hulunbuir city on the Chinese border with Russia.

According to a report from the official Xinhua news agency, the positive case in Shanghai was found after mass testing following infections of a security inspector at Pudong International Airport and his wife.

Shanghai’s health authority later reported two new locally transmitted cases in the city on Sunday, both connected to the Pudong cases.

Mainland China reported another 11 asymptomatic cases on November 21, down from 18 on the previous day.

It has so far reported an accumulated total of 86,431 COVID-19 cases, with the official death toll at 4,634.

-with AAP