WASHINGTON - The Trump administration is warning U.S. companies that it will investigate those that discriminate against qualified American workers in favor of foreigners.

The Justice Department issued a warning Monday as companies began applying for coveted skilled-worker visas. That program is used mostly by technology companies to bring in programmers and other specialized workers from other countries.

The Trump administration has long promised to crack down on businesses that discriminate against U.S. workers by using the visa program to hire foreigners. U.S. Citizenship and Immigration Services also announced Monday that it would step up its reviews of employers that use H-1B visas.

The Obama administration sued companies for violating the Immigration and Nationality Act's anti-discrimination provisions. But Monday's statement appears to be a new warning to employers not to displace Americans.