UK Prime Minister Boris Johnson has been moved to the intensive care unit after his coronavirus symptoms worsened, Downing Street has said.
Mr Johnson, who tested positive for coronavirus 10 days ago was admitted to St Thomas' Hospital on Sunday initially for tests but his health has since deteriorated.
Earlier at the government's daily briefing, Mr Raab had said Johnson was still very much in charge and that he was in "good spirits" after spending a "comfortable" night in hospital.
The spokesman said a decision was made at 7pm to move him to the ICU. He was moved on the advice of his medical team and is receiving "excellent care".
The prime minister has asked Foreign Secretary Dominic Raab to deputise "where necessary".
The statement read: "Since Sunday evening, the prime minister has been under the care of doctors at St Thomas' Hospital, in London, after being admitted with persistent symptoms of coronavirus.
"Over the course of this afternoon, the condition of the prime minister has worsened and, on the advice of his medical team, he has been moved to the intensive care unit at the hospital."
Mr Johnson's symptoms included a high temperature and a cough.
Earlier on Monday, he tweeted that he was in "good spirits".
Last month, the prime minister's spokesman said if Mr Johnson was unwell and unable to work, Mr Raab, as the first secretary of state, would stand in.
Less than three years ago, Dominic Raab did not have a presence in the government.
Now, as foreign secretary and first secretary of state, he is the de-facto second-in-command to Mr Johnson.
The staunch Brexiteer ran for the Conservative Party leadership last year but he was knocked out in the second round.