Shenzhen, China, reportedly ordered 100 large companies, including Foxconn, into a closed loop to stop the spread of COVID-19.

Foxconn claimed that business was “normal” at its Shenzhen plants and that it would abide by regulations to maintain secure production.

As it fights COVID-19, the Chinese city of Shenzhen instructed 100 significant enterprises, including iPhone manufacturer Foxconn, to build up “closed-loop” systems, according to a document attributed to the local administration and making the rounds online on Monday. Although Reuters was unable to independently verify the document, a notice at the CNOOC Ltd. office in Shenzhen stated that the building would be closed for seven days until July 31. Staff members would be required to work from home and conduct daily COVID testing.A CNOOC representative was unable to provide an instant response.

An inquiry for comment was not answered by the Shenzhen administration.

Foxconn, a Taiwanese company, claimed that business at its Shenzhen facilities was “regular” and that it will abide by regulations to maintain secure production.

According to the directive allegedly issued by Shenzhen’s department of industry and information, big corporations like BYD, Huawei Technologies, and ZTE should limit their entry and exit into the alleged loopholes.

BYD, ZTE, and Shenzhen-based drone manufacturer DJI Technology declined to comment, while Huawei did not immediately respond to requests for comment.

On Monday, Bloomberg published an article on Shenzhen’s measure.

Shanghai, the center of China’s economy, attempted to maintain factories operating during its lockdown in April and May by using “closed loop” operations, where employees live and work on-site, but businesses claimed the arrangements presented significant challenges.

Shenzhen, a center for technology with about 18 million residents, reported 21 new locally transmitted COVID-19 cases on Sunday, up from 19 the previous day.

Despite the fact that the number of cases is still low by international standards, a slight increase over the past week has forced local authorities to increase their level of caution in order to follow the central government’s “dynamic zero” strategy of suppressing outbreaks as soon as they occur.

Shenzhen has locked residential compounds and buildings that have been deemed to be more dangerous but has not ordered the outright closure of companies or strict restrictions on people’s movements.

Since Monday, many businesses, eateries, and public places have requested proof of a COVID test within 24 hours.

During an outbreak in March, Shenzhen instituted one week of so-called “slow living,” during which time inhabitants underwent numerous rounds of testing and spent the majority of their time at home. Every few days, one member of each household was permitted to leave the house to get supplies.