JPMorgan Chase will temporarily shut about 1,000 bank branches, roughly 20%, to protect employees and reduce the spread of the coronavirus, according to a memo the bank sent to employees Wednesday.

Beginning Thursday, the bank's remaining roughly 4,000 branches will be open as usual but operating on reduced hours, as JPMorgan Chase becomes the first national lender to temporarily close operations as a precaution against the escalating health crisis.

Many of the branches remaining open have drive-through windows and glass partitions separating the bank teller from customers, the bank said.

The bank said it will pay its branch employees for their regularly scheduled hours, even if the hours they work are reduced or the branch where they work is closed.

Financial advisers, small-business bankers and home-lending advisers will start working from home on Thursday. Private client, relationship and business bankers will also get a one-time financial incentive for March, April and May.

The bank is also offering free meals to employees of the community and consumer banking division who work in offices where there is an on-site cafeteria and free lunch on Thursdays for branch employees.

The bank also relaxed the dress code, allowing staff to work in T-shirts and sneakers, and gave everyone two additional paid days off.

Thasunda Duckett, chief executive officer of Chase Consumer Banking, said that the bank is balancing "the fact that we are essential to the communities we serve" with the need to protect employees.

"We are doing everything we can to step up for our country, our customers and for all of you," Duckett wrote in the memo.

Chase is also stepping up cleaning at branches and will send a specialized cleaning team to a branch within an hour if they report a "confirmed or highly likely COVID-19 case," according to the memo.