A total of 3,507 domestically transmitted cases with confirmed symptoms were reported on Monday across more than a dozen provinces and municipalities, the National Health Commission said, up from 1,337 a day earlier.
China's caseload is still tiny by global standards, but health experts said the rate of increase in daily cases over the next few weeks will be a crucial factor in determining whether China's tough "dynamic clearance" approach - which aims to contain each outbreak - is still effective against the rapidly spreading Omicron variant.
Jilin officials should step up the preparation of temporary hospitals and designated hospitals and make use of idle venues to ensure all infections and their close contacts are isolated, a local Communist Party authority-backed paper said, citing the provincial head of the Party.
The number of new asymptomatic cases, which China does not classify as confirmed cases, stood at 1,768 compared with 906 a day earlier.
There were no new deaths, leaving the death toll unchanged at 4,636.
As of March 14, mainland China had reported 120,504 cases with confirmed symptoms, including both local ones and those arriving from outside the mainland.