China’s COVID-19 cases remain elevated, with Shanghai rolling out mass testing in nine districts as the financial hub seeks to stamp out infections, while the gaming enclave of Macau extended its lockdown.

China reported 510 cases for Sunday after infections jumped to 580 on Saturday — the highest since May 23. The latest hotspots include the Guangxi autonomous region in the south of the country, which recorded 112 cases Sunday, following a spike to 244 the previous day, and the northwestern province of Gansu, which reported 211 infections for Sunday, up from 158 on Saturday.

Shanghai reported 17 cases for Sunday, compared with 26 on Saturday. The new infections were found in areas under quarantine. The situation in Shanghai remains “relatively severe,” with pressure from both a rebound in local cases and imported infections, said Zhao Dandan, deputy head of the city’s health bureau.

In response to the flare-up, Shanghai is rolling out mass testing to ensure early detection. Nine districts will carry out testing blitzes between July 19-21, with residents will be required to take two tests within the three-day period.

Tianjin, a port city near Beijing, also plans a mass-testing drive after finding two cases, CCTV reported.

Macau extended its citywide lockdown on Saturday as the gaming hub struggles to contain its worst COVID outbreak since the pandemic started. All non-essential businesses are required to remain closed through July 22, authorities said, extending measures that began on July 11 and were initially due to last a week.

The shutdown will prolong the plight of casinos, which are burning through millions of dollars every day and earning no revenue.

Macau added 22 cases, suggesting the lockdown hasn’t stopped local transmission. The outbreak, which started on June 18, has swelled to a total of 1,755 infections. While small by global standards, it is the largest ever flare-up for the city of 680,000 residents.

More than 2,000 tourists are stranded in the coastal city of Beihai, which has been placed under lockdown as infections surge, state media reported Sunday. As of Saturday, the city of 1.8 million people in southwestern Guangxi province had reported more than 450 positive cases, prompting local health authorities to roll out rounds of mass testing for residents.

The director of Beihai’s city health commission, Tang Gang, and the head of Haicheng district, Su Kuangfeng, have been dismissed for failing in their COVID prevention work less than a week since the outbreak was detected in the city.