The Justice Department this morning urged firms petitioning for H-1B visas, documents permitting U.S. companies to employ foreign workers in specialty occupations, to not discriminate against U.S. workers.

The caution comes as the government is starting to accept employers' H-1B visa requests for the next fiscal year.

"The Justice Department will not tolerate employers misusing the H-1B visa process to discriminate against U.S. workers," Acting Assistant Attorney General Tom Wheeler of the Civil Rights Division said. "U.S. workers should not be placed in a disfavored status, and the department is wholeheartedly committed to investigating and vigorously prosecuting these claims."