Beijing plans to test tens of thousands of people after four new Covid-19 cases were found in a suburban district on Friday, as a new outbreak prompts school closures and flight cancellations across the country.
China has maintained a staunch zero-Covid strategy with strict border closures, lengthy quarantines and targeted lockdowns.
But the world's most populous nation is now scrambling to tamp down dozens of infections across several provinces.
The latest flare-up has prompted the grounding of hundreds of flights, the closure of scenic areas and schools and a flurry of stay-home orders in affected housing compounds.
The outbreak was traced to an elderly couple who were in a group of domestic tourists who flew from Shanghai to Xi'an, Gansu province and to Inner Mongolia.
Dozens of cases have since been linked to their trip, with close contacts in at least five provinces and regions -- including sparsely populated Inner Mongolia and the capital Beijing.
In response, officials in northwestern Beijing's Changping district have ramped up contact tracing and tightened Covid safety protocols, state media reported Friday, with 35,000 people due to be tested.
On Monday, disease-hit Erenhot in Inner Mongolia banned travel in and out of the city and ordered residents to stay at home, while an outbreak in Ejin county prompted authorities earlier this week to shutter tourist sites and restrict travel.
State-owned tabloid Global Times warned Wednesday that the Inner Mongolia cases could worsen supply chain disruptions and hinder coal imports from neighboring Mongolia.
China logged 28 new locally transmitted Covid-19 cases on Thursday, 15 more than the previous day, the National Health Commission said in a statement Friday.