British Prime Minister Boris Johnson's condition is improving and he is able to sit up in bed and engage with clinical staff, finance minister Rishi Sunak said on Wednesday as Johnson remained in intensive care battling COVID-19.

Johnson was admitted to St Thomas' hospital on Sunday evening with a persistent high temperature and cough and was transferred to intensive care on Monday.

The 55-year-old British leader, who tested positive for the new coronavirus nearly two weeks ago, has received oxygen support but has not been put on a ventilator.

"The latest from the hospital is that the prime minister remains in intensive care where his condition is improving," Sunak said at a daily government coronavirus news conference. "I can also tell you that he has been sitting up in bed and been engaging positively with the clinical team."

Later, Downing Street issued a brief statement, expected to be the last update on Johnson's condition until Thursday. "The Prime Minister continues to make steady progress. He remains in intensive care," it said.

On the same day, U.S. President Donald Trump also shared his thoughts on Johnson's conditions with reporters at a briefing on the coronavirus.

"I just spoke with the representatives of the UK and I think that their great prime minister is doing much better today, or at least better," Trump said. "But certainly he has had a tough bout and he is still going through a tough time, but he seems to be doing better, and that's good." 

Since Johnson was moved to intensive care, leaders around the world have sent well wishes to the British Prime Minister, with many describing him as "a friend" to their nations and wishing him a speedy recovery. 

Heads of governments in countries including the United States, Russia, France, Canada, Qatar, Afghanistan, Israel and Ireland were among the ones who have expressed support for Johnson. 

"I've gotten to know him. He's just such an incredible guy," Trump said. "It was just so shocking to see that because you know what that means - intensive care is a big deal with regard to what we're talking about. That's a very big deal. Very scary deal."

Foreign Secretary Dominic Raab, Johnson's designated deputy, told reporters on Tuesday in a daily briefing that he was confident Johnson will pull through. "If there is one thing I know about this prime minister, he's a fighter."

Deadliest phase in Britain

While Johnson is out of action, Britain is entering what scientists say is the deadliest phase of the outbreak and the government is pondering the question of when to lift lockdown measures that are playing havoc with the economy.

As of Thursday, the country has recorded 60,733 confirmed cases and 7,097 deaths.

But the number of new infections and hospital admissions is starting to show signs of flattening, Stephen Powis, medical director of the National Health Service, told the news conference.

"We are beginning to see the benefits (of the lockdown) I believe but the really critical thing is that we have to continue following instructions - we have to continue following social distancing, because if we don't the virus will start to spread again," he said.

Dominic Raab will chair a meeting on Thursday to discuss how to deal with a review of the lockdown measures.

"We committed that there would be a review in and around three weeks (from the start of the lockdown). That review will be based on the evidence and the data provided by SAGE," said Sunak, referring to the Scientific Advisory Group for Emergencies.

Britain's uncodified constitution, a collection of sometimes ancient and contradictory precedents, offers no clear, formal "Plan B" if a prime minister is incapacitated. In essence, decisions have to be made collectively by the cabinet.

Should Raab become unwell, Sunak will be the next in line to take over.

In the latest of a raft of measures to rescue the economy and society from the worst effects of the crisis, he announced an extra 750 million pounds (930 million U.S. dollars) of funding for charities so that they could continue their work.

(With input from Reuters)

(Cover image: Boris Johnson speaks after being announced as Britain's next Prime Minister at The Queen Elizabeth II center in London, Britain July 23, 2019. /Reuters)