(CNN) As US companies face record losses amid the coronavirus pandemic, the FBI is warning that American businesses now have something else to worry about: fraud by employees seeking to take advantage of the pandemic.

In a report disseminated Monday to companies across the nation, and obtained by CNN, the FBI's Office of Private Sector notified members of private industry they should be on the lookout for fake doctors notes and falsified documentation from employees claiming positive Covid-19 test results.

The bureau report warned that the steps a company must take to stop business operations and sanitize work spaces could lead to significant financial loss.

As one example, the FBI report described an incident in March where an employee working for an unidentified "critical manufacturing company" told their bosses they had tested positive for Covid-19 and submitted what appeared to be documentation from a medical facility.

"In response, the company shut down the affected manufacturing facility to disinfect the location, ceasing production and halting delivery of necessary materials to the plant," the FBI report stated. "The company notified all employees at the facility, including four workers who had close contact with the reportedly infected employee and were required to self-quarantine."

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