China has reported more Covid-19 cases as it enters the third week of its current outbreak, while some cities add rounds of mass testing in the effort to stamp out locally-transmitted infections, reports Reuters.

The highly infectious Delta variant has been detected in more than a dozen cities since July 20, and officials have asked local government authorities to rigorously track infections and close loopholes in control efforts.

"A laxity of mind should be firmly overcome," the National Health Commission said in a statement that called for the outbreak to be curbed.