US President Donald Trump on Tuesday signed an order that will enter into force a part of his “Buy American/Hire American” election campaign platform.

This order requires tougher enforcement of rules governing the hiring of foreign workers in the United States and a tightening of the requirement that US government agencies use American-made products, reported Voice of America.

Under Trump’s order, government agencies are being directed to review their procurement practices and require that exceptions to the “buy American” rules be approved by the heads of those agencies.

Officials also said government procurement portions of existing trade agreements would be reviewed to see whether US companies get the same chance to sell products to the governments of US trading partners that foreign firms get in Washington.

Another review is aimed at rules governing visas issued to foreigners with certain skills that are in demand (H-1-B visas). The program is supposed to help employers attract foreign workers with skills that are scarce in the United States. Trump administration officials say they are concerned that companies are hiring foreigners who do the same work as Americans at lower wages.

Government agencies are being directed to conduct “top to bottom” reviews of these rules and laws, and report problems and recommendations that could bring about changes.