China on Monday indefinitely postponed the annual Beijing marathon scheduled to be held later this month as it fights a country-wide surge in Covid-19 cases including in the capital.

Beijing authorities also restricted entry to the city on Monday, and sent out directives asking citizens not to leave unless necessary.

“The epidemic situation is severe and complex, and the epidemic risk and prevention pressure faced by the capital continue to increase,” a Beijing official said on Monday.

Organisers of Beijing’s marathon said in a statement on Sunday that the run would be postponed until further notice “…in order to prevent the risk of the epidemic spreading (and) effectively protect the health and safety of the majority of runners, staff and residents.”

More than 30,000 people were expected to take part in the event on October 31.

A marathon in Wuhan, the central Chinese city where the first Covid-19 cases were detected in 2019-end, was cancelled on Sunday.

The China-Mongolia border city of Ejin Banner, a region hit hard in the latest coronavirus flare-up, told all residents and tourists on Monday that they must stay indoors to prevent the spread of the outbreak.

The Chinese mainland on Sunday reported 35 new locally transmitted Covid-19 cases, the national health commission said in its daily report on Monday, taking the total number of cases over 160 in the new outbreak, which has now spread to 11 provinces.

All of them are said to be the highly transmissible Delta variant.

The latest outbreak, said to have been triggered by tour groups travelling out of the northern autonomous region of Inner Mongolia, comes as the country’s top health official warned of more cases.

Authorities have suspended inter-provincial tour groups in five areas where cases have been detected, including Beijing.

There is increasing risk that the outbreak might spread further, helped by “seasonal factors”, Mi Feng, spokesman at the National Health Commission, said on Sunday.

It’s likely to have raised concerns over China’s ability to maintain its zero-tolerance approach to the virus, especially leading up to the 2022 Winter Olympics, slated to begin on February 4, to be held in and around Beijing.

Despite the small numbers reported in the recent outbreaks, China has stuck to a zero-Covid strategy by implementing lockdowns, mass testing of populations, at times more than once, and mass vaccination drives, the largest in the world.

Health authorities said on Sunday that about 75.6% of China’s 1.4bn population had received complete vaccine doses as of October 23, or some 1.068bn.

Mainland China has reported more than 96,700 cases until Sunday and the number of deaths is at 4,636.