House Democrats want the White House to hand over any tapes that President Trump may have of his private conversations with fired FBI Director James Comey.

"Under normal circumstances, we would not consider credible any claims that the White House may have taped conversations of meetings with the President," Rep. John Conyers, D-Mich., and Rep. Elijah Cummings, D-Md., wrote in a letter to White House Counsel Don McGahn. "However, because of the many false statements made by White House officials this week, we are compelled to ask whether any such recordings do in fact exist. If so, we request copies of all recordings in possession of the White House regarding this matter."

That request was sparked by a tweet from President Trump, who seemed to imply that such recordings exist while discouraging Comey from talking to the press. "James Comey better hope that there are no 'tapes' of our conversations before he starts leaking to the press!" Trump tweeted Friday morning.

Trump's team declined to say if such recordings exist. "The president has nothing further to add on that," White House press secretary Sean Spicer told reporters Friday afternoon.

Cummings and Conyers, respectively the top Democrats on the Oversight and Government Reform Committee and the Judiciary Committee, suggested Trump might have violated a law against witness intimidation.

"The president's actions this morning — as well as his admission yesterday on national television that he fired Director Comey because he was investigating Trump campaign officials and their connections to the Russian government — raise the specter of possible intimidation and obstruction of justice," they wrote. "The president's actions also risk undermining the ongoing criminal and counter-intelligence investigations and the independence of federal law enforcement agencies."

The law pertains to official testimony, however, not conversations with the press. As a rule, presidents can withhold information about internal deliberations from Congress under the doctrine of executive privilege. That's because the White House-led executive branch of government is co-equal with Congress under the Constitution.

Trump might have undermined his ability to claim executive privilege, according to some legal experts, by claiming in the letter firing Comey that the FBI director repeatedly assured him he is not being investigated. "Those [public descriptions of the conversations] could be considered a waiver of any presidential privilege protecting Trump's interactions with the former FBI director," Reuters reported, citing analysis from a pair of law professors.