A United Airlines plane from San Francisco was placed on lockdown in London on Friday after a passenger on board displayed symptoms consistent with the coronavirus.

United Flight 901 arrived in London shortly after 9 a.m. local time. Once the plane landed, passengers on board said the captain told them to stay in their seats because someone had "taken ill" while aboard, Sky News reported .

Andy West, one of the passengers on board, told Sky that crew members then said the passenger may have the coronavirus, which is officially called COVID-19. The passenger was reportedly taken to the back of the plane by airline staff.

Passengers were asked to complete a contact form for the UK's public health department, and were allowed to disembark normally about 25 minutes later.

According to Sky, West said passengers had not received any advice about what to do, including early symptoms to be aware of or whether to self-quarantine.

It was not immediately clear whether the passenger had been in China recently, where the virus originated, nor whether the individual had been in contact with others who had been in the impacted regions.

More than 64,000 people worldwide have contracted the coronavirus, officially known as COVID-19, and at least 1,380 have died. A case was recently confirmed in London.

The Daily Mail reported that passengers on seven other planes at Heathrow had been screened as possible coronavirus cases. A spokesperson for United told Business Insider that the airline was providing special guidance to crew members for how to deal with possible cases, as well as disinfecting planes after each international flight.

"The safety of our customers and employees is our top priority and we are working closely with Public Health England regarding this individual case," the spokesperson said. "Our crews are trained and ready to respond to anyone on board the aircraft who may become ill in flight and we continue to follow additional precautions recommended by the Public Health England. The aircraft has undergone a deep clean, which includes cleaning all surface areas and overhead bins."

The spokesperson said the airline had not received information on whether the case was confirmed to be coronavirus or something else. Public Health England did not immediately return a request for comment from Business Insider.

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