Facebook has closed its three London offices after an employee based in Singapore has been tested positive for coronavirus.
The employee visited the London operations between 24 and 26 February.
As a result, the offices have been closed since 3pm today (Friday) for deep cleaning over the weekend and staff have been asked to work from home. They will reopen on Monday.
Facebook has contacted those who have had direct contact with the person to ask them to self-isolate and be vigilant in monitoring symptoms.
A spokesman for the company said: "An employee based in our Singapore office who has been diagnosed with Covid-19 visited our London offices [on] 24-26 February 2020. We are therefore closing our London offices until Monday for deep cleaning and employees are working from home until then."
Omnicom offices OMD and PHD closed their offices in Fitzrovia last week while an employee was being tested for coronavirus. They reopened on Monday.
There are now 163 cases of coronavirus in the UK. The virus, officially called Covid-19, was discovered in Wuhan, China, at the end of last year.