China has imposed a strict lockdown on nearly half a million people in a province near the capital after a small surge in cases.
Authorities have warned that the outbreak in Hebei province's Anxin county was still "severe and complicated".
Anxin would be "fully enclosed and controlled", with restrictions similar to those imposed in Wuhan, where the outbreak first emerged.
The move comes after Beijing recorded 14 new cases in the last 24 hours, bringing the total number of cases linked to the Zinfai wholesale food market to 311.
According to state news agency Xinhua, businesses in Anxin had supplied freshwater fish to the Xinfadi market.
Head of IRGC's intelligence organisation announced as dead
Six injured after Iranian attack on residential area in Kuwait
Russian drone attack on Ukraine's Odesa kills three
US, Iran and mediators make push for 45-day ceasefire
US snatches airman from Iran as Trump, Israel ratchet up pressure
