The daily count of new COVID-19 cases in mainland China surged to 1,807 on Sunday, the highest daily figure in two years, data from the National Health Commission showed.

Two of the country's biggest cities, Shenzhen and Shanghai, have imposed strict virus measures.

Shenzhen officials imposed a lockdown for one week. Nonessential workers are ordered to stay home and adults have been asked to undergo three P.C.R. tests. Similarly, Shanghai has entered a partial lockdown. Residents are barred from leaving the city unless it is necessary.

The spike in coronavirus cases has led to allowing rapid antigen tests for public use and resulted in the dismissal of senior officials for their slack response to the ongoing health crisis.

State media tabloid Global Times reported that China must strive to achieve a new breakthrough in its COVID policy.

The surge prompted health authorities to allow the public to buy rapid self-test kits for the first time to help detect infections quickly, as some experts said China's earlier strategy based on nucleic acid test – requiring medical workers to take samples – had become harder with the fast-spreading Omicron variant.

Meanwhile, about 300,000 Covid-19 patients and their close contacts in Hong Kong are now under home quarantine, according to the city's Chief Executive Carrie Lam.

Also read: NATO stands divided as Turkey declares it will not sanction Russia