BEIJING: All 17 million people in the Chinese tech hub of Shenzhen spent their first full day under lockdown Monday, as restrictions spread across Shanghai and other major cities to combat an outbreak challenging the nation’s zero-tolerance Covid strategy.

The southern city of Shenzhen imposed the measure to counter an Omicron flare-up in factories and neighbourhoods linked to nearby Hong Kong, which is recording scores of daily deaths as the virus runs rampant.

Major Apple supplier Foxconn suspended its operations in Shenzhen, the company said Monday, as the lockdown bit hard into economic activity across the factory hub. Shenzhen is one of ten cities nationwide to have locked down all residents, though the measure was taken Monday in some parts of other major hubs including Dalian, Nanjing and Tianjin, which neighbours the capital.

Health officials have warned tighter restrictions could be on their way, as concerns mount over the resilience of China’s “zero-Covid” approach in the face of the highly-transmissible Omicron variant.

Authorities reported 2,300 new virus cases nationwide on Monday and almost 3,400 a day earlier, the highest daily figure in two years.

“There have been many small-scale clusters in urban villages and factories,” Shenzhen city official Huang Qiang said at a Monday briefing. “This suggests a high risk of community spread, and further precautions are still needed.”

Photos shared with AFP by a Shenzhen resident showed housing compound entrances blocked by large plastic barriers, as residents swapped jokes on social media about their rush to grab laptops from offices before the lockdown. Tech stocks plummeted on the Hong Kong exchange on Monday, as concerns over the impact of the virus spread in Shenzhen — home to hubs for Foxconn, as well as Huawei and Tencent — spooked investors.