Health officials in China said Thursday that they will be stepping up coronavirus testing and screening countrywide amid growing concern of a domestic rebound in cases.

“We need to expand Covid-19 testing and screening to quickly find the source of infections and prevent a resurgence in coronavirus cases,” said Song Shuli, a spokesperson for the National Health Commission.

The announcement comes after both Jilin and Liaoning provinces in the northeast of the country reported new locally transmitted cases this week.

Earlier on Thursday, Chinese state media reported that the city of Wuhan, ground zero for the Covid-19 pandemic, had begun a “10-day battle” to test all 11 million of its citizens for coronavirus after the public health authorities identified six locally transmitted cases.