Donald Trump’s former personal lawyer provided the US House intelligence committee with new documents and may hand over more, the panel’s chairman said after a day-long hearing behind closed doors.

The Democratic representative Adam Schiff told reporters that Michael Cohen was cooperative and the eight-hour hearing was “very productive”. He did not say what the new documents related to and declined to comment on the substance of Cohen’s testimony.

“We had requested documents of Mr Cohen. He has provided additional documents to the committee. There may be additional documents that he still has to offer and his cooperation with our committee continues,” Schiff said.

However, several news outlets reported the documents showed alleged edits to the false written statement he delivered to Congress in 2017 saying that discussions around the construction of a Trump Tower in Moscow ended in January 2016.

What those edits are exactly is still unknown, but the documents are meant to support the allegations Cohen made last week that Jay Sekulow, Trump’s former personal attorney, had edited his statements before the House and Senate intelligence committees.

Cohen, who, in public testimony last week before a different House committee, called Trump a “racist”, “conman” and “cheat”, arrived for his testimony before Schiff’s committee carrying a brown file folder and wheeling a black suitcase.

Two congressional sources, speaking on condition of anonymity, said Cohen was due to face questions from lawmakers on the issue of a pardon from his former boss. The sources added that Trump’s representatives maintained that Cohen’s team first raised the issue of receiving a pardon while the former lawyer’s representatives have said the opposite.

The sources said Cohen also would probably be questioned about the extent of Trump’s personal involvement in pursuing a tower project in Moscow during the 2016 presidential campaign. Trump at the time denied any links to Russia but has since defended the proposed tower project, which never materialized.

Cohen’s lawyer, Lanny Davis, said in a statement that Cohen had now spent 16 hours testifying before the intelligence committee.

“Mr Cohen responded to all questions truthfully and has agreed at the request of chairman Schiff to provide additional information in the future, if needed. He also offered to answer additional questions from Republican members. He remains committed to telling the truth and cooperating with authorities,” Davis added.

Patrick Boland, a spokesman for Schiff, declined to comment on the reports.

Cohen’s testimony on Wednesday was the latest in a series of appearances before congressional panels, most of them private. His televised 27 February testimony before the House oversight committee was followed by a rapid expansion of Democratic investigations focusing on Trump.

Intelligence panel members also were expected to question Cohen on Wednesday about Trump’s discussions with advisers in 2017 about how to respond when news reports first surfaced revealing that senior campaign figures, including his son Donald Trump Jr; son-in-law, Jared Kushner; and campaign chairman Paul Manafort met in June 2016 with the Kremlin-linked Russian lawyer Natalia Veselnitskaya, one of the sources said.

Trump’s son arranged the meeting after being promised “dirt” on Trump’s Democratic opponent, Hillary Clinton. When news of the meeting broke, Trump Jr issued a statement saying it was set up to discuss adoption policy, not politics. He later admitted he had been expecting intelligence on Clinton.

The special counsel Robert Mueller is completing an investigation into whether Trump’s campaign conspired with Russia and whether the president has unlawfully sought to obstruct the probe. Trump has denied collusion and obstruction. Russia has denied election interference.

Cohen is due to report to prison on 6 May to begin a three-year sentence after pleading guilty in a separate case last year to criminal charges including tax evasion, bank fraud and campaign finance violations.