British Prime Minister Boris Johnson has been taken into the intensive care unit in hospital after his COVID-19 worsened, his office says.
British Prime Minister Boris Johnson was on Monday admitted to intensive care after being hospitalised with coronavirus, with foreign minister Dominic Raab to take over his duties "where necessary", his Downing Street office said.
"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," said the Downing Street press release.
"The PM has asked Foreign Secretary Dominic Raab... to deputise for him where necessary," it added.
The prime minister was moved in case he needed to use a ventilator, the government added.
Mr Johnson was admitted to St Thomas' Hospital in London on Sunday with a temperature and a cough after testing positive for coronavirus on March 27, becoming the most high-profile world leader infected with the disease that has spread rapidly across the globe.
The 55-year-old had been self-isolating in his Downing Street flat but on Sunday evening was driven to a nearby state-run hospital on the advice of his doctor.
Officials said it was a "precautionary step" but questions had earlier been raised about whether the Conservative leader could still run the country.
The British government was criticised for initially refusing to follow other European countries in requiring people to stay home as the virus spread.
And Mr Johnson himself said in early March that he was still shaking hands with people.
But two weeks ago he ordered a nationwide lockdown and Britain is now in the grip of a serious outbreak.
Over 50,000 cases and more than 5,000 deaths have been recorded so far, with a latest daily toll of 439.
Health Secretary Matt Hancock and the heir to the throne, Prince Charles, have both been infected with coronavirus, although they have since recovered.
Housing minister Robert Jenrick told BBC television that the prime minister had been working "phenomenally hard" during the crisis, adding that he would be finding it "very frustrating" to be ill.
Mr Johnson is not known to have any underlying health issues, although he has struggled with his weight, but some questioned if he should have taken more time off.
Junior health minister Nadine Dorries, who also had coronavirus but has recovered, added: "Many with #COVID19 are felled by fatigue/temperature and use isolation to sleep and recover.
"Boris has risked his health and worked every day on our behalf to lead the battle against this vile virus."
Sarah Vine, a newspaper columnist and wife of senior cabinet minister Michael Gove, added: "Boris has worked non-stop throughout his illness - and now we see the result."
US President Donald Trump said he was "hopeful and sure" Mr Johnson would recover, calling the prime minister "a friend of mine" and a "great leader".
European Commission chief Ursula von der Leyen wished Johnson "a speedy and full recovery".
"My thoughts are with Prime Minister Boris Johnson and his family this evening," she tweeted.
Her reaction was echoed by the EU's Brexit negotiator Michel Barnier, who is recovering in quarantine after also testing positive.
"Wishing Boris Johnson all the best and a speedy recovery. My thoughts are with you and your family," Mr Barnier tweeted.
French President Emmanuel Macron gave his "full support to Boris Johnson, his family and the British people at this difficult time".
"I hope he will rapidly overcome this ordeal," he tweeted.
Italy's Prime Minister Giuseppe Conte tweeted in English that "the Italian people is with the UK in these difficult times. We are one for each other. Get well soon Boris Johnson!"
World Health Organization chief Tedros Adhanom Ghebreyesus said he was "thinking of my friend Boris Johnson tonight, and sending my and WHO's heartfelt good wishes as he battles the coronavirus."
"I know the NHS and its dedicated health workers will be looking after you," he tweeted.
Dutch Prime Minister Mark Rutte said that "on behalf of the Dutch cabinet, I wish Boris Johnson, his family and the British people lots of strength during this difficult time."
"I hope to be able to speak to him soon in good health," Mr Rutte tweeted.
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