WASHINGTON—Before officially taking office, the incoming Trump administration directed House Speaker Mike Johnson to strip legal assistance from victims of floods, hurricanes, and fire that had been included in an emergency supplemental spending bill in December.

Johnson readily complied, sources familiar with the negotiations said, and the move came even after President Donald Trump’s election campaign ran heavily on the claim that Democrats had “abandoned” flood victims, particularly those in western North Carolina. The funding cut, amounting to $103 million, has not been previously reported.