China has postponed the Beijing marathon until further notice, amid a surge in coronavirus infections.
It comes as the country's top health official warned that a fresh outbreak of cases is expected to spread further, reports BBC.
China has reported more than 133 cases across 11 provinces so far. All of them have been linked to the highly transmissible Delta variant.
The latest surge is considered the largest outbreak in the country since Nanjing in August this year.
It has raised concerns over China's ability to maintain its zero-tolerance approach to the virus, especially leading up to the 2022 Winter Olympics.
How significant is the Beijing marathon?
Held annually since 1981, the Beijing marathon is one of China's biggest local sporting events.
The race traditionally begins at Tiananmen Square and ends in Celebration Square in Beijing's Olympic Park.
Around 30,000 people were expected to take part in the marathon, which was scheduled to happen on October 31.
Marathon organisers said it was cancelling the event "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."
The latest surge is believed to have been spread by local tour groups visiting other provinces and cities.
How is China dealing with this surge?
China has enforced travel restrictions, ramped up testing and urged heightened vigilance in a bid to stamp out the latest outbreak.
Officials have banned travel agencies from arranging cross-provincial tours that involve affected regions.
Meanwhile, authorities in the capital Beijing have said they will not allow people with travel history to affected counties into the city.
Many countries such as Australia have switched from a zero-tolerance policy to living with the virus.
But China has stuck to a zero-Covid strategy by implementing harsh lockdowns, mass testing and pursuing mass vaccination drives - about 75.6% of China's population, or 1.068 billion people, had received complete vaccine doses as of Saturday.
However, it has recently suffered sporadic local outbreaks of Covid, mostly due to the Delta variant.