SHENZHEN, CHINA (REUTERS) - A Covid-19 outbreak linked to a bar in China's capital Beijing is "ferocious", local government spokesman Xu Hejian said at a news conference on Sunday (June 12).

A total of 166 cases have been linked so far to the outbreak at the Chaoyang Heaven Supermarket Bar, which emerged last week.

Authorities reported 33 new cases on Sunday as of 3pm. The capital has reported 1,997 local Covid-19 cases since April 22.

While China's infection rate is low by global standards, President Xi Jinping has doubled down on a zero-Covid-19 policy that authorities say is needed to protect the elderly and the medical system, even as other countries try to live with the virus.

So far the country of 1.4 billion has seen a total of just 5,226 fatalities.

There has been a renewed tightening of Covid-19 curbs in Beijing since Thursday, 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.

On Saturday, the commercial hub of Shanghai began mass testing to contain a jump in cases tied to a popular beauty salon. The city has only recently started to emerge from a strict two-month lockdown.