Brenda Goh, Norihiko Shirouzu

SHANGHAI (Reuters) – General Motors, Volkswagen (DE) Group China said Monday that the Shanghai lockdown was not affecting their operations. The city had been put in place to prevent the spread COVID-19.

In joint ventures with Chinese state-owned automaker SAIC Motor Corp, the two companies own factories in the City.

A spokesperson for GM told Reuters that the company’s manufacturing plants were functioning normally.

China’s biggest city was divided by the Huangpu River on Sunday to enable “staggered” coronavirus screening.

GM’s Shanghai plants are located east of the river, in an area that has been secured from Monday through Friday to allow authorities to conduct mass testing.

Shanghai did not comment immediately on the company’s measures to maintain production lines, although it stated that “closed-loop systems” can be used by factories.

Tesla (NASDAQ):, which has a plant on the east bank of the river as well, suspended production Monday, according to sources.

Volkswagen Group China claimed that operations in Anting and Shanghai were unaffected. It also stated it is closely monitoring the situation.

Anting is located in Shanghai west. Lockdown is set to begin April 1.

However, Volkswagen’s operations in Changchun (northern China) are still suspended. Because of the COVID-19 lockdown, it has been stopped from March 14.