CNN  — 

All of Amazon’s US warehouse employees will once again be required to wear masks indoors beginning on Monday, whether they are vaccinated or not, the company confirmed to CNN Business on Friday.

The move comes one day after Amazon (AMZN) said it would delay its office return date for corporate employees until early next year. The back-to-back announcements highlight how one of America’s largest employers is rethinking its coronavirus policies in the face of rising infections linked to the Delta variant.

“In response to the concerning spread of new Covid-19 variants in the US and guidance from public health authorities and our own medical experts, we are requiring face coverings indoors regardless of vaccination status,” said Kelly Nantel, an Amazon spokesperson, in a statement to CNN Business.

“We are monitoring the situation closely and will continue to follow local government guidance and work closely with leading medical healthcare professionals, gathering their advice and recommendations as we go forward to ensure our buildings are optimized for the safety of our teams,” Nantel said.

A growing number of big companies have shifted their policies for corporate and frontline workers as the pandemic has worsened, in some cases requiring vaccinations. But for now, Amazon does not appear to be taking that step: Nantel declined to comment on whether the company is considering a vaccine mandate.

The announcement was first reported by Bloomberg.

Amazon (AMZN) had relaxed its mask requirement on May 24 for fully vaccinated US warehouse workers, at least in areas where local regulations did not continue to require them. More recently, Amazon (AMZN) said it would stop offering on-site Covid-19 testing by the end of July, citing the wide availability of testing and vaccines.

Amazon’s business boomed during the pandemic as households and companies leaned on its various services. But the company was criticized early on in the pandemic after some workers said the company had not provided sufficient protective gear or adequately sanitized its warehouses, leading to protests and lawsuits.