US technology giant Facebook on Friday said it was shutting its London office until Monday for a “deep clean” after an employee visiting from Singapore was diagnosed with coronavirus.

“An employee based in our Singapore office who has been diagnosed with COVID-19 visited our London offices from February 24 to 26, 2020,” the company said in a statement.

“We are therefore closing our London offices until Monday for deep cleaning and employees are working from home until then.”

The company said it was getting in touch with individuals who had direct contact with the person infected, and had asked them to self-isolate and monitor for any potential symptoms.

Coronavirus has infected more than 100,000 people across 91 countries, according to an AFP tally, while more than 3,400 people have died.

A total of 163 people have currently tested positive for the virus in Britain, and one person has died, health authorities said Friday.