WASHINGTON — Former US President Donald Trump has hit back at his daughter Ivanka after she distanced herself from his unfounded claims of mass voter fraud.

A probe into the 2021 US Capitol riots on Thursday aired a previously unseen clip of Ivanka Trump rejecting the claims.

Trump said Ivanka had not been looking at election results and "had long since checked out".

Democrats argue the mob attack on Congress was the culmination of a months-long attempted coup by Trump.

Graphic footage and testimony of the Jan. 6, 2021 raid on the Capitol in Washington DC was televised on Thursday by the US House of Representatives select committee.

The prime-time hearing drew 20 million viewers on the TV networks.

The broadcast included a clip of testimony by former US Attorney General Bill Barr saying he had repeatedly dismissed the outgoing president's claims that mass voter fraud had caused him to lose the election.

Another excerpt was aired of Ivanka Trump's interview from April with the committee when she was asked about her reaction to Barr's assessment.

"It affected my perspective," Trump said. "I respect Attorney General Barr so I accepted what he was saying."

Trump responded on his social media site, Truth Social, on Friday, labeling the inquiry a "WITCH HUNT!"

"Ivanka Trump was not involved in looking at, or studying, Election results," he added.

"She had long since checked out and was, in my opinion, only trying to be respectful to Bill Barr and his position as Attorney General (he sucked!)."

The president also lambasted Barr as a "coward", while continuing to insist the election was "rigged".

Trump was a presidential adviser in her father's administration and accompanied him to the rally that he hosted outside the White House just before the US Capitol attack unfolded.

A handful of voter fraud cases have been prosecuted since the November 2020 election, but no concrete evidence has emerged of such criminal activity on any scale that could have swayed President Joe Biden's victory.

The House select committee will hold another five hearings over the coming fortnight.

Next Monday's session will attempt to show that Trump and his inner circle knew he had lost the election, but spread claims of voter fraud anyway.

The panel has conducted 1,000 interviews and gathered 140,000 documents over the year-long inquiry. — BBC