WASHINGTON—President Trump signed an executive order on Tuesday that seeks to give his political appointees far-reaching control over federal agencies that for decades have operated independently of White House influence.

President Donald Trump signed a sweeping executive order to bring independent agencies under control of the White House, which will almost certainly be challenged in court.

A new executive order will set up a court challenge over whether Trump has the power to direct investigations by independent agencies that oversee corporations, labor unions, banks and federal elections.