WASHINGTON (AFP) - The US congressional committee investigating the Jan 6 assault on the Capitol by supporters of former president Donald Trump issued a sweeping request on Wednesday (Aug 25) for records related to the attack.

The House Select Committee asked the National Archives and seven government agencies for a vast trove of documents related to the attempt by Trump supporters to block the certification by Congress of Democrat Joe Biden's November presidential election victory.

Among the records and documents being sought are communications from Trump, members of his family, his top aides, his lawyers and dozens of other former members of his administration.

"The Select Committee to Investigate the Jan 6 Attack on the United States Capitol is examining the facts, circumstances, and causes of the Jan 6 attack," said Representative Bennie Thompson, the Democratic chairman of the committee.

"Our Constitution provides for a peaceful transfer of power, and this investigation seeks to evaluate threats to that process, identify lessons learned and recommend laws, policies, procedures, rules, or regulations necessary to protect our republic in the future," Thompson said.

The committee has held one hearing so far, on July 27, when four Capitol and Washington police officers testified about defending the Senate and House of Representatives from a mob of Trump supporters on Jan 6.

Requests for records were directed to the National Archives, Pentagon, Department of Homeland Security, Interior Department, Justice Department, FBI, National Counterterrorism Centre and the Office of the Director of National Intelligence.

The committee asked for the records to be turned over by Sept 9.

It said it was seeking to discover "how the Jan 6 events fit in the continuum of efforts to subvert the rule of law, overturn the results of the Nov 3, 2020 election, or otherwise impede the peaceful transfer of power."

Among the records requested from the National Archives were "all documents and communications related to the mental stability of Donald Trump or his fitness for office."

Trump has consistently refused to acknowledge his defeat to Biden and continues to make unfounded claims that he won the election.

The real estate mogul was impeached by the Democratic-controlled House in January for inciting insurrection but was acquitted by the Senate.