U.S. Labor Department investigators say Cisco Systems discriminated against U.S. workers by favoring immigrigant visa holders, according to a Bloomberg report.

The Department of Labor’s office of Contract Compliance Programs concluded that Cisco secured visas for foreign employees instead of hiring U.S. citizens for job openings. It paid the visa holders less than their American counterparts, according to unnamed sources Bloomberg quotes.

The DOL found the discrimination after a routine audit and is discussing settlement of a violation notice sent to the tech giant earlier.

Bloomberg says that a Cisco spokeswoman denied some of the allegations, saying visa holders are paid on the same basis as U.S. workers.

Cisco, which employs more than 73,000 people internationally, has a large campus in Research Triangle Park. It employed about 1,600 visa holders in 2017, including those holding H-1B visas that allow employers to hire highly skilled workers temporarily in specialty occupations.