Wells Fargo has pushed back plans for employees to return to corporate offices by a month in response to the rise in U.S. coronavirus cases.

The bank is now aiming to kick off the first phase of its plan on Oct. 4, from a previous Sept. 7 target, according to a memo Thursday from Chief Operating Officer Scott Powell. The move applies to employees who are currently working remotely, not those who are already working on site, Powell said.

Wells Fargo, the fourth biggest U.S. bank by assets, is joining a growing list of corporations that are pushing back return dates or mandating that employees be vaccinated or wear masks amid a nationwide surge driven by the more contagious delta variant.

Last week, Citigroup said that even vaccinated employees would need to wear masks at corporate offices. Tech giants, including Facebook and Alphabet, now mandate that employees who wish to return to offices be vaccinated. Giant asset manager BlackRock also said Thursday that it is pushing office return plans back by a month to October, according to Bloomberg, which earlier reported the Wells Fargo news.

The bank also encouraged, but did not require, employees to get vaccinated and said that almost 90% of its workforce had responded to an internal vaccine questionnaire, according to the memo obtained by CNBC. The bank declined to comment beyond the memo.

“We will continue to monitor the situation and make further adjustments if required,” Powell told employees. “Please take care of yourselves and your families.”

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