Nine Million Residents in China's Qingdao to Undergo Covid-19 Testing

The new alert system, which will classify all areas as either "medium", "high" or "very high" risk, is an attempt to bring transparency and uniformity to restrictions introduced to combat the spread of the disease.

Read also: Boris Johnson Considering Second Round of Coronavirus Lockdowns in UK

"This is a critical juncture and it is absolutely vital that everyone follows the clear guidance we have set out to help contain the virus," a Downing Street spokesperson said.

Several urban centers in northern England have already been hit with a range of curbs on social life such as a ban on different households mixing, but the south has escaped stricter restrictions for now.

The national death toll from coronavirus in Britain is more than 42,000 — the worst in Europe.

Globally more than 37 million people have now been infected, and at least 1.07 million have died.

Trump claims immunity

Trump's doctors gave the president the all-clear Saturday to return to the campaign trail after he was ruled no longer a coronavirus transmission risk, and on Sunday he said he tested "totally negative".

But he has yet to be declared virus-free, and his immunity claim is unproven.

"It looks like I'm immune for, I don't know, maybe a long time and maybe a short time, it could be a lifetime, nobody really knows, but I'm immune," Trump told Fox News.