Citigroup Inc. executives said their top takeaway from Asia, which faced the coronavirus earlier than the U.S., has been the potential for a resurgence of cases as governments relax shelter-in-place orders.

Management said the bank is taking a site-by-site approach to reopening offices that have been shuttered to slow the spread of COVID-19. Even in the U.S., there is "unevenness" in the spread of the virus, necessitating a site-specific approach, executives said during an April 15 earnings call. In Hong Kong, the company has about one-third of its employees back in the office and the rest still working remotely.

"I would say lesson one — that we're watching very closely — is the resurgence of cases as people start to come back in. And so I think we've got to be very mindful about when and how we, in fact, do that," said CEO Michael Corbat.

Management also reported a slight revenue decline in Asia, which they attributed to the virus. They said consumer spending in Asia slowed due to travel restrictions and that similar spending patterns have emerged in the U.S. and just beginning in Mexico.

In the U.S., Citigroup has seen card spend activity decline by approximately 30% in the last week of March, led by travel spending declining 75% and dining and entertainment dropping by 60%. Retail spending, which includes apparel and department stores, was 50% lower while spending on essential items was 10% higher, an executive said.

READ MORE: Sign up for our weekly coronavirus newsletter here, and read our latest coverage on the crisis here.