WASHINGTON (REUTERS) - Former US President Donald Trump pressed the Justice Department during his waning weeks in office to join his failed effort to overturn his election defeat based on his false claims of voting fraud, but its leaders refused, with one decrying the "pure insanity" of the claims, documents released on Tuesday (June 15) showed.

The House of Representatives Oversight and Reform Committee, which sought the records, outlined a series of overtures made by the Republican former president, then-White House Chief of Staff Mark Meadows and an outside private attorney, Mr Kurt Olsen, pushing the department to act on Mr Trump's claims.

The department ultimately did not join the effort and numerous courts rejected lawsuits seeking to overturn election results in various states.

Congress also is investigating the deadly Jan 6 assault on the US Capitol by a mob of Mr Trump supporters trying to stop the formal certification of Democratic President Joe Biden's election victory.

"These documents show that President Trump tried to corrupt our nation's chief law enforcement agency in a brazen attempt to overturn an election that he lost," said Committee Chairwoman Carolyn Maloney, a Democrat.

These overtures were separate from the revelations that the Trump-era Justice Department secretly sought the phone records of at least two Democratic lawmakers, a move that led Mr Biden's Attorney-General Merrick Garland on Monday to vow to strengthen policies aiming to protect the department from political influence.

The department under outgoing Attorney-General William Barr, who left his post on Dec 23, and his short-term replacement Jeffrey Rosen decided not to act on the false claims of voting fraud.

Mr Biden took office on Jan 2.

The emails showed that Mr Meadows asked Justice Department officials to investigate an unfounded conspiracy theory called "Italygate" alleging that US electoral data was changed in Italian facilities with the knowledge of the CIA.

On Jan 1, Mr Meadows sent Mr Rosen a link to a YouTube video detailing the theory. Mr Rosen forwarded the email to then-acting Deputy Attorney-General Richard Donoghue, who replied: "Pure insanity."

The documents also showed that Mr Trump pressured Mr Rosen when he was deputy attorney-general to have the Justice Department take up the election fraud claims.

The emails showed Mr Rosen declined to arrange a meeting between Justice Department officials and Mr Trump's personal lawyer Rudy Giuliani about his false claims that the November election was stolen from Mr Trump.

Mr Meadows had asked Mr Rosen to help arrange the proposed meeting with Mr Giuliani, the emails showed.

"I flatly refused, said I would not be giving any special treatment to Giuliani or any of his 'witnesses,' and re-affirmed yet again that I will not talk to Giuliani about any of this," Mr Rosen wrote to a Justice Department colleague on Jan 1.

Mr Giuliani had played a prominent role in promoting Mr Trump's false election claims.

Mr Trump, through an assistant, sent Mr Rosen a Dec 14 email with documents purporting to show evidence of election fraud in northern Michigan - a debunked allegation that a federal judge had already rejected.

Two weeks later, on Dec 29, Mr Trump's White House assistant emailed Mr Rosen, who by then was the acting attorney-general, and other Justice Department lawyers a draft legal brief that they were urged to file at the US Supreme Court.

The department never filed the brief. Emails released by the House committee showed that Mr Olsen, a Maryland lawyer involved in writing Mr Trump's draft brief, repeatedly tried to meet with Mr Rosen but was unsuccessful.

The draft brief backed by Mr Trump argued that changes made by the states of Georgia, Michigan, Wisconsin, Arizona, Nevada and Pennsylvania to voting procedures amid the Covid-19 pandemic to expand mail-in voting were unlawful.

Mr Biden won all those states.

Similar arguments were made in a lawsuit filed by Mr Ken Paxton, the Republican attorney-general of Texas and a Mr Trump ally. The U.S Supreme Court rejected that long-shot lawsuit in December.

Representatives for Mr Trump did not immediately respond to a request for comment.

The document release comes ahead of the House Oversight committee's hearing with FBI director Christopher Wray and General Charles Flynn, brother of former national security adviser Michael Flynn, who has also voiced Mr Trump's election conspiracy theories.