WASHINGTON (REUTERS) - A senior aide and a retired federal judge who advised former US vice-president Mike Pence are set to testify on Thursday (June 16) to the House of Representatives committee investigating the Jan 6, 2021, attack on the Capitol, the panel said on Wednesday.

Mr Greg Jacob, who served as counsel to Mr Pence, and retired US Appeals Court Judge J. Michael Luttig, who was an informal adviser, are scheduled to testify at the third of an expected six public hearings the committee has planned for this month.

The hearing is due to focus on Mr Pence's role that day in overseeing formal congressional certification of Mr Joe Biden's 2020 election victory over then-president Donald Trump, who has made false claims that the election was stolen through widespread voting fraud.

Subsequent hearings are expected to focus on topics including what the Democratic-led committee describes as Mr Trump's efforts to replace officials at the Justice Department with appointees who would help promote his efforts to overturn the election results.

Trump supporters stormed the Capitol in an attempt to block the certification of the election results, attacking police and sending lawmakers fleeing for their safety. Some protesters chanted "hang Mike Pence" and set up a makeshift gallows outside the Capitol.

The committee is looking into Mr Trump's contacts with Mr Pence in urging him to refuse to certify the election and the rioters'chants that Mr Pence should be hanged. Mr Pence refused Mr Trump's requests that he block the certification.

Mr Pence in February of this year said Mr Trump, under whom he served as vice-president for four years, was wrong to believe that Mr Pence had the power to reverse the outcome of the election.

"I had no right to overturn the election," Mr Pence told an audience in Florida.