Former president Donald Trump has told four former senior aides not to comply with a congressional probe into the January 6 attack on Congress, US media reported Thursday.

Politico and The Washington Post both reported that ex-advisors Mark Meadows, Kash Patel, Dan Scavino and Steve Bannon were told not to cooperate with the formal House investigation into the riot by Trump supporters, which critics have labelled an outright insurrection.

The reports came hours after the release of a damning Senate report detailing Trump's efforts to subvert the Justice Department and overturn his November election loss to Joe Biden.

Trump's lawyers argued in a letter to the four that his communications and records are protected from disclosure by executive privilege and attorney-client privilege.

The Select Committee to Investigate the January 6th Attack has called the four ex-advisers, and other people involved in the unrest, to help it piece together the ties between Trump's White House and the hundreds of Trump backers who forced their way into the Congress, halting a joint session meant to confirm Biden as president.

At the time Meadows was White House chief of staff; Scavino handled social media for Trump; Bannon was a former political strategist who remained active in Republican operations; and Patel was a White House national security advisor whom Trump named to a senior Pentagon job following his election loss.

The four were ordered by the January 6 committee to hand over documents and appear for interviews with investigators next week.

Legal experts have raised doubts that Trump can claim executive privilege over his actions in his final weeks in office to prevent his aides from talking.

But the issue has not been tested much in courts and the White House has said it would waive privilege on Trump's records to an extent in order to help with the probe.

And Trump's defiance could force the committee into legal fights that could stretch out the investigation.

"The former president is still trying to stonewall subpoenas," said committee member Adam Schiff in a tweeted statement.

"This time, lawbreaking witnesses must weigh the prospect of criminal prosecution," he warned.

"Americans deserve answers. We will make sure they get them."