The Wuhan Marathon, which had been due to take place Sunday, has been postponed at short notice as worries increase over a coronavirus resurgence in China ahead of the 2022 Beijing Winter Olympics.
China reported 26 new domestic Covid-19 cases on Sunday, in an outbreak that has become latest test of the country's zero-tolerance approach with just over 100 days until the start of the Games.
Authorities have been racing to contain virus infections via mass testing of residents and targeted lockdowns.
But with the rise in cases, organisers of the Wuhan Marathon said in a statement released late last week that they would postpone Sunday's event in the central Chinese city "to prevent the risk of epidemic spread".
The event was expected to have 26,000 participants, taking part in races including a full marathon and half marathon, in the city where coronavirus was first identified towards the end of 2019, state media reported.
The organising committee said it would refund the registration fees of contestants who successfully signed up.
China has wrestled down the number of infections to a trickle by deploying aggressive, mass testing and keeping its borders extremely tight.
It remained unclear if next Sunday's 40th edition of the Beijing marathon would go ahead as planned. Organisers did not immediately respond when contacted by AFP.
Beijing will on Wednesday mark 100 days to go before the Winter Olympics, beginning February 4, with organisers admitting earlier this month they "face great pressure" because of Covid-19.
The Games could be the most restricted mass sporting event since the pandemic began, with no international spectators allowed and a vaccine mandate for anyone entering a strictly enforced "bubble".
Athletes must be vaccinated or face 21-day quarantine upon entry to China.
Ahead of the Winter Olympics, Beijing has started to offer residents booster jabs for the coronavirus.
The latest outbreak was linked to an elderly couple who were in a group of several tourists.
They started in Shanghai before flying to Xi'an, Gansu province, and Inner Mongolia.