Apple temporarily shut three stores on Wednesday as Covid cases rise around the country.

A store in Miami is closed through Thursday, and a store in Ontario and another in Annapolis, Maryland are closed through Friday, according to Apple’s website.

The closures raise questions about the impact of the Covid pandemic on the holiday shopping season amid concerns from public health authorities about the impact of the Omicron variant, which appears to be more transmissible.

“We regularly monitor conditions and we will adjust our health measures to support the wellbeing of customers and employees,” an Apple representative said in a statement. “We remain committed to a comprehensive approach for our teams that combines regular testing with daily health checks, employee and customer masking, deep cleaning and paid sick leave.”

Apple said that store employees will take Covid-19 tests before reopening, so whether these stores re-open as scheduled on the website will depend on coronavirus conditions. Apple’s retail employees have had access to weekly at-home tests provided by the company since earlier this year.

Apple also announced yesterday that it will require face masks for customers at all stores in the United States.

In addition to store closings, Apple has adjusted individual store policies in response to regional conditions, including an emphasis on customer pickups via online purchases instead of in-store shopping and increasing the amount of space to social distance.

Apple closed all of its stores in 2020 in response to the Covid-19 pandemic. All stores re-opened earlier this year. Since then, Apple has sometimes closed individual stores because of coronavirus conditions, including a Texas location last week.

California, where Apple is headquartered, has imposed a month-long indoor mask mandate.