William Barr testifies at a Senate Judiciary Committee hearing on his nomination to be attorney general of the United States on Capitol Hill in Washington, U.S., January 15, 2019. REUTERS/Yuri Gripas

WASHINGTON (Reuters) - President Donald Trump’s attorney general nominee William Barr pledged at his confirmation hearing on Tuesday to support and uphold the False Claims Act, a law that lets whistleblowers file lawsuits to help the federal government recover losses due to fraud.

“I will diligently enforce the False Claims Act,” Barr told Republican Senator Charles Grassley, marking a reversal from prior comments he made in which he declared the law was an abomination and unconstitutional.