A US House of Representatives committee investigating the January 6 insurrection at the Capitol has issued its first set of subpoenas to four allies of former president Donald Trump's administration.
Former chief of staff Mark Meadows, former chief strategist Steve Bannon, former White House deputy chief of staff for communications Dan Scavino and former Defence Department official Kash Patel were all instructed to produce materials and appear for depositions in mid-October, committee Chairman Bennie Thompson said in a statement late on Thursday.
A representative for Mr Meadows said he declined to comment. Mr Bannon and Mr Scavino could not be reached for immediate comment.
Mr Patel said in a statement he was "disappointed, but not surprised" the committee issued a subpoena before seeking his voluntary co-operation.
"We will fight the Subpoenas on Executive Privilege and other grounds," Mr Trump said in a statement.
The committee investigating the insurrection is comprised of nine lawmakers. Representatives Liz Cheney and Adam Kinzinger, who both voted to impeach Trump earlier this year, are the lone Republican members.
In letters to each of the four witnesses, Mr Thompson said investigators believe they have relevant information about the lead-up to the insurrection.
Writing to Mr Meadows, Mr Thompson wrote the committee had "credible evidence" of his involvement in events within the scope of the investigation. That includes the "planning and preparation of efforts to contest the presidential election and delay the counting of electoral votes."
Mr Meadows was also reportedly in communication with the organisers of the January 6 rally, Mr Thompson said said.
The committee also pointed to Mr Bannon's prediction on January 5 that "all hell is going to break loose tomorrow."
A mob of Trump supporters swarmed the Capitol on January 6 as Congress was moving to certify then President-elect Joe Biden's victory in the 2020 presidential election. The process was delayed for several hours as then-Vice President Mike Pence, House Speaker Nancy Pelosi and other members of Congress, as well as journalists and staffers fled from rioters.
Nearly 600 people have been arrested on charges tied to the deadly attack.
The committee conducted its first hearing in July, listening to testimony from four police officers who were injured and verbally abused as the rioters broke into the building and repeated Trump's baseless accusations of widespread election fraud.
Former Attorney General William Barr has said the US Justice Department found no evidence of fraud that could have affected the election's outcome.
A partisan review of the 2020 presidential election commissioned by Arizona Republicans has confirmed President Joe Biden's victory over Donald Trump in the state's most populous county, according to a draft report of the review's findings.
At least nine people were died on the day of the insurrection, including a Trump supporter who was shot as she attempted to break into the House chamber.
Two police officers died by suicide in the days that immediately followed, and a third officer collapsed and died after engaging with the rioters. An additional two police officers who responded to the insurrection also died by suicide this summer.