Federal Bureau of Investigations Director, James B. Comey, asked the Justice Department to publicly reject President Trump’s claims that President Barack Obama ordered the wiretapping of his phones.

The New York Times reports that Comey, who made the request after Trump publicly accused Obama on Twitter Saturday of the violation, has been working to get the Justice Department to reject the claim. The accusation not only serves as an attack on Obama’s character, but insinuates that the FBI broke the law, officials said.

Comey’s request puts the nation’s top law enforcement official in the position of questioning the president’s truthfulness. The confrontation between the two underscores just how dangerous it is for the president and his aides to accuse the former president of a conspiracy.

Showing no indication that he would back down, Trump demanded a congressional inquiry into whether Obama had abused power of federal law enforcement agencies before the Nov. 2016 presidential election. In a statement from his spokesman, the president called “reports” on the wiretapping “very troubling.” He also said Congress should examine them as part of its investigation into Russia’s alleged efforts to disrupt the presidential election.

“President Donald J. Trump is requesting that as part of their investigation into Russian activity, the congressional intelligence committees exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016,” press secretary, Sean Spicer, said in a statement Sunday. “Neither the White House nor the president will comment further until such oversight is conducted.”

A spokesman for Obama and his former aides called the accusation completely false, saying the nation’s 44th president never ordered any wiretapping of a U.S. citizen.