WASHINGTON - U.S. President Donald Trump signed an order Monday requiring federal agencies to prove they are not replacing qualified American workers with people from other countries.

The White House said the executive order would help prevent federal agencies from "unfairly replacing American workers with low-cost foreign labor."

The order requires all federal agencies to complete an internal audit to show whether they are hiring U.S. citizens and nationals for competitive service positions.

Trump said his move was partly prompted by the announcement of the Tennessee Valley Authority (TVA) that it intended to outsource 20% of its technology jobs to companies based in foreign countries, using H-1B visas.

The executive order also comes as some foreign journalists at Voice of America await a ruling on whether their J-1 visas will be renewed following an agencywide review of such visas.

Trump told reporters Monday that he had fired the chair of the TVA, Skip Thompson, because he was hiring foreign workers and getting paid too much.

He also threatened to remove other federally appointed board members if they keep hiring foreign labor.

"If you betray American workers, you will hear two words: 'You're fired,'" he said.

The TVA is a federally owned corporation created in 1933 to provide flood control, electricity generation and economic development to the Tennessee Valley, a region that was hard hit by the Great Depression.

The visa review at the U.S. Agency for Global Media (USAGM), which oversees VOA, is part of the changes implemented since Michael Pack took up his appointment as chief executive officer.

The VOA has 62 contractors and 14 full-time foreign employees who are in the United States on J-1 visas, an entry permit for individuals with unique skills, such as the command of multiple languages.

Asked by VOA how Trump's new executive order would impact the news organization's J-1 visas, the White House only provided a link to a federal government jobs website that described employment of noncitizens.

A USAGM spokesperson said in a statement that the case-by-case visa review was aimed at improving agency management, protecting U.S. national security and ensuring that hiring authorities are not misused.

Journalist groups, including PEN America and the National Press Club, have said the visa renewal delays could put many VOA journalists at risk of threats to arrest if they are forced to return to their home countries.

An unknown number of journalists at the other USAGM networks, which include Radio Free Europe/Radio Liberty, Radio Free Asia, the Office of Cuba Broadcasting and Middle East Broadcasting Networks, are also affected by the visa review.

New entries on J-1 visas are among several categories of visas that were temporarily banned by the Trump administration in response to the coronavirus pandemic. The administration has argued that foreign workers should not take jobs away from U.S. citizens during the economic downturn.