LANZHOU -- A total of 34 residential compounds in Northwest China's Gansu province had been put under closed-off management as of Thursday due to the emergence of COVID-19 cases, local authorities said Friday.

The communities are scattered in the cities of Lanzhou, Zhangye, Jiayuguan and Longnan, said Liang Chaoyang, deputy head of Gansu's COVID-19 prevention and control leading group office.

Residents in areas under closed-off management should be under strict home quarantine and stay indoors.

The province had collected more than 26 million samples in mass nucleic acid testing by Thursday to screen COVID-19 infections.

Nearly 548,600 volunteers have joined the fight against the epidemic.

From Oct 18 to 28, Gansu had logged 75 local confirmed cases in the latest COVID-19 resurgence.