Shenzhen in south China's Guangdong Province has tightened measures to contain the latest outbreak of COVID-19.

The city will conduct three rounds of mass testing, local health authorities announced on Sunday via an official Wechat account.

All businesses except necessary industries should suspend operations and workers are advised to work at home from March 13 to March 20, according to the release.

During the period, the city transportation including subways and buses will be halted. All Shenzhen residents are advised not to leave the city unless absolutely necessary.