The House is investigating whether President Donald Trump lied in his written answers to former Special Counsel Robert Mueller, the House's top lawyer said in federal court as Congress seeks access to a trove of materials that Mueller's team collected.

House general counsel Douglas Letter made the statement to the U.S. Court of Appeals as part of a House lawsuit seeking access to grand jury materials collected as part of the Mueller probe, according to CNN, which reported the House is investigating whether Trump lied to Mueller's team.

'Did the President lie? Was the President not truthful in his responses to the Mueller investigation?' Letter asked. He said the House needed access to the full range of materials to assess this.

President Donald Trump provided written answers to questions by Robert Mueller. He said he didn't recall discussing WikiLeaks with Roger Stone

Letter's statement comes days after former Trump deputy campaign manager Rick Gates testified that Trump spoke with informal advisor Roger Stone about WikiLeaks in 2016.

Trump said in response to written questions by Mueller, following months-long negotiations: 'I do not recall discussing WikiLeaks with him,' in reference to Stone.

'Nor do I recall being aware of Mr. Stone having discussed WikiLeaks with individuals associated with my campaign,' Trump said.

The House lawyers made a similar claim in a filing in late September, saying redactions in the grand jury materials indicate Trump may have lied.

'Not only could those materials demonstrate the president’s motives for obstructing the special counsel’s investigation, they also could reveal that Trump was aware of his campaign’s contacts with WikiLeaks,' the lawyers wrote, Politico reported then.

The statement by the House Democratic lawyer follows testimony in the trial of Roger Stone that appeared to contradict Trump's written statement that he did not recall speaking to Stone about WikiLeaks

Trump provided written answers to Special Counsel Robert Mueller's questions in consultation with his lawyers during the Russia probe

House Democrats, led by Speaker Nancy Pelosi, are suing in federal seeking access to grand jury materials from the Russia probe. They prevailed at the U.S. District Court level

Lawyers for jailed former Trump campaign chair Paul Manafort said he 'recalled' being asked by Trump to be kept 'updated' on WikiLeaks releases of hacked Democratic emails. But Mueller's report redacted underlying evidence which the House lawyers called 'critical' to the committee's investigation.

House Speaker Nancy Pelosi has encouraged the House Intelligence Committee to try to limit the scope of its impeachment inquiry. The panel has been working weekends and scheduling back-to-back public hearings as it seeks to meet a goal of wrapping up its inquiry by Thanksgiving as possible.

Some Democrats have pushed for a wider probe that could include issues relating to Trump's business earnings and whether they constitute an unconstitutional 'emolument, and potential obstruction of justice unearthed by the Russia probe. House lawyers continue to fight on a number of fronts to gain access to materials including Trump's taxes.

Letter's statement came during a Monday hearing at the U.S. Circuit Court of Appeals for the D.C. Circuit, a court one notch below the U.S. Supreme Court in supremacy.

A lower court ruled in House Democrats' favor. Judge Beryl Howell ruled late last month that the House was engaged in a process that merited an exemption from grand jury secrecy rules.

'Even in cases of presidential impeachment, a House resolution has never, in fact, been required to begin an impeachment inquiry,' Howell wrote days before the House voted on a resolution setting up a formal inquiry.

The House wants redactions from Mueller's 448-page report.

Howell wrote: 'In carrying out the weighty constitutional duty of determining whether impeachment of the President is warranted, Congress need not redo the nearly two years of effort spent on the Special Counsel’s investigation, nor risk being misled by witnesses, who may have provided information to the grand jury and the Special Counsel that varies from what they tell.'