The US House of Representatives is looking into whether President Donald Trump lied in his written testimony for special counsel Robert Mueller's federal investigation into Russian meddling in the 2016 election.
House general counsel Doug Letter told a federal appeals court in Washington on Monday that politicians were examining whether Mr Trump's written answers to investigators were untruthful.
"Did the president lie? Was the president not truthful in his responses to the Mueller investigation?" Mr Letter asked the US Court of Appeals for the District of Columbia Circuit.
He was arguing that the House needed access to uncensored grand jury material in Mr Mueller's report.
Mr Mueller submitted his report to US Attorney General William Barr in March after completing a 22-month investigation.
It detailed Russia's campaign of hacking and propaganda to boost Mr Trump's candidacy in the 2016 election, and extensive contacts between the president's campaign and Moscow.
House lawyers had already disclosed the investigation into Mr Trump's written responses in September.
They said in a court filing that the unredacted Mueller report could reveal whether Mr Trump lied about his knowledge of his campaign's contacts with WikiLeaks, which published hacked Democratic Party emails.
The White House did not immediately respond to a request for comment.
Last week, former deputy campaign chairman Rick Gates suggested in testimony during a criminal trial that Mr Trump talked to longtime adviser Roger Stone about WikiLeaks during the 2016 campaign.
Mr Gates testified that after finishing a July 2016 call from Mr Stone, Mr Trump indicated that "more information would be coming", in an apparent reference to WikiLeaks.
His testimony appeared to conflict with sworn written statements that Mr Trump gave Mr Mueller.
"I do not recall discussing WikiLeaks with him," Mr Trump said of Mr Stone in his written responses to the special counsel.
"Nor do I recall being aware of Mr Stone having discussed WikiLeaks with individuals associated with my campaign.”
A federal judge on October 25 granted the House's request for access to the grand jury secrets in the Mueller report.
The Trump administration appealed against the ruling to the US Court of Appeals for the DC Circuit, which on Monday debated whether to put the October ruling on hold while it considered the legal merits of the dispute.