U.K. Prime Minister Is in the ICU with Coronavirus After 'Worsening' — but He's Not on a Ventilator

U.K. Prime Minister Boris Johnson was moved into intensive care on Monday night local time as his condition “worsened” more than week after he announced he’d contracted the novel coronavirus, PEOPLE confirms.

However, Johnson remained awake and had not been placed on a ventilator.

Aides described the move as precautionary as he was being treated for the respiratory illness, which causes the disease COVID-19.

Foreign Secretary Dominic Raab has been placed in charge by Johnson “where necessary,” according to a spokesman for the prime minister, who announced the health update in a statement.

It was a seemingly rapid deterioration after Johnson had tweeted Monday that he was in “good spirits” while hospitalized.

His exact condition remained unclear. A spokesman said only that “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.”

“The PM is receiving excellent care, and thanks all NHS staff for their hard work and dedication,” the spokesman said.

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A spokesperson previously told PEOPLE that Johnson’s symptoms included “a temperature and a cough” but described claims on a Russian news site that he was on a ventilator as “disinformation.”

Johnson tweeted earlier Monday that he’d gone into the hospital on Sunday night “on the advice of my doctor.”

“I went into hospital for some routine tests as I’m still experiencing coronavirus symptoms,” Johnson wrote. “I’m in good spirits and keeping in touch with my team, as we work together to fight this virus and keep everyone safe.”

In a follow-up post, the Conservative party leader — who revealed his positive test for COVID-19 on March 27 — heaped praise on the small army of U.K. medics fighting the virus within the country’s National Health System.

“I’d like to say thank you to all the brilliant NHS staff taking care of me and others in this difficult time,” said Johnson. “You are the best of Britain. Stay safe everyone, and please remember to stay at home to protect the NHS and save lives.”

WILL OLIVER/EPA-EFE/Shutterstock From left: Carrie Symonds and U.K. Prime Minister Boris Johnson

The prime minister 55, is receiving treatment at St. Thomas’s hospital in central London, which stands directly opposite the Houses of Parliament and is little more than a five-minute stroll from the Downing Street home he shares with 32-year-old fiancée Carrie Symonds.

Symonds, who is pregnant with the couple’s first child, is also struggling with the symptoms of COVID-19. Taking to Twitter on Saturday, she wrote that she’d spent the past week in bed due to the virus.

“I haven’t needed to be tested and, after seven days of rest, I feel stronger and I’m on the mend,” she wrote.

“Being pregnant with Covid-19 is obviously worrying,” Symonds tweeted in a follow-up post. “To other pregnant women, please do read and follow the most up to date guidance which I found to be v reassuring.”

Despite being hospitalized, a No. 10 spokesperson confirmed to PEOPLE Monday that Johnson was continuing to receive updates and briefings.

The spokesperson also confirmed that with Johnson away from Downing Street, the Monday morning meeting of the U.K. government’s coronavirus committee was chaired by Foreign Secretary Raab. A meeting of the British cabinet scheduled for Tuesday has also been postponed.

Speaking at a Downing Street news conference on Monday, Raab told reporters that Johnson was taken to hospital as “a precautionary step as he continues to have persistent coronavirus symptoms 10 days after first having tested positive for the virus.”

Raab added, “The PM had a comfortable night in hospital and is in good spirits.”

“He’s still in hospital under observation,” he continued. “He’s being given regular updates on developments and he continues to lead the government.”

President Donald Trump is among those to have sent good wishes to Johnson.

“All Americans are praying for him. He’s a great friend of mine, a great gentleman and a great leader,” Trump said on Sunday, adding that he was sure the prime minister would be fine because he’s “a strong person”.

Meanwhile, Sir Keir Starmer — who was elected leader of the U.K.s opposition Labour party on Saturday — wished the prime minister a “speedy recovery.”