U.K. Prime Minister Boris Johnson was admitted to hospital Sunday after testing positive for the novel coronavirus last week, with the symptoms failing to disappear.

A Downing Street spokesperson said: “On the advice of his doctor, the Prime Minister has tonight been admitted to hospital for tests.”

“This is a precautionary step, as the Prime Minister continues to have persistent symptoms of coronavirus ten days after testing positive for the virus.

“The Prime Minister thanks NHS [National Health Service] staff for all of their incredible hard work and urges the public to continue to follow the Government’s advice to

Read more: UK premier admitted to hospital as 'precautionary step'