Beijing's recent outbreak of Covid-19 that has been linked to bars in the capital is "explosive" in nature, widespread in scope and complex, a Beijing government spokesman said in a briefing on Saturday.

The capital has reported 46 new local Covid cases on Saturday as of 3pm local time, health official Liu Xiaofeng said at the same briefing.

Of a total of 1,946 local Covid cases reported since April 22, a total of 115 cases were connected to the bar cluster, Liu said.

The capital on Thursday started to tighten some Covid curbs again, with at least two districts — including its most populous, Chaoyang - closing certain entertainment venues after a flare-up in a busy neighbourhood known for its nightlife, shopping and streets of embassies.

The cases were linked to a drinking establishment known as Heaven Supermarket Bar. Infections have since surged, with Beijing saying on Saturday that all of the 61 new cases uncovered in the city on Friday had either visited the bar or had links to it.

So far a total of 69 cases linked to the bar have been reported, with the afflicted from 14 of Beijing's 16 districts, throwing the city of 22 million back into a state of anxiety.

Beijing had relaxed less than two weeks ago widespread Covid curbs imposed to fight a major outbreak that began in April.

With the Covid resurgence, the sprawling Universal Beijing Resort late on Friday rescinded a plan to reopen, saying it would remain closed until further notice. Three of its workers had visited the bar, according to Beijing authorities. Read full story

Meanwhile, commercial hub Shanghai began a round of mass testing for nearly all of its 25 million residents as authorities sought to contain an outbreak tied to a popular beauty salon.

Authorities have ordered PCR testing for all residents in 15 of Shanghai's 16 districts this weekend, with five districts barring residents from leaving their homes during the testing period.

The new tests come just 10 days after the city lifted a gruelling two-month lockdown aimed at eliminating the community spread of Covid-19. On Saturday, Shanghai reported seven new local symptomatic cases for the previous day, of which six were detected outside of quarantined areas.

The city also recorded nine new local asymptomatic cases, up from six the previous day.

In total, mainland China reported 210 new coronavirus cases for June 10, of which 79 were symptomatic and 131 were asymptomatic, the National Health Commission said on Saturday.

That was up from 151 new cases a day earlier — 45 symptomatic and 106 asymptomatic infections, which China counts separately.

There were no new deaths, leaving the nation's fatalities at 5,226. As of Friday, mainland China had confirmed 224,659 cases with symptoms.