Donald Trump has been requested to appear before Congress and give evidence for his impeachment trial.
The 45th US president earlier this week rejected the charge of "incitement of insurrection" that was put to him over the 6 January riots in Washington DC.
He was impeached following the violence at the US Capitol which saw five people die.
The House of Representatives last month impeached Mr Trump before he left office, and the case is heading for a trial in the Senate.
Mr Trump was charged after he told a crowd to "fight" his election defeat, before the mob headed to the Capitol.
In a rejection of the impeachment lodged by his lawyers, Mr Trump's defence claimed he "fully and faithfully executed his duties as president".
It went on to say that Mr Trump's baseless claims that he won the election were protected by freedom of speech and the first amendment to the US constitution.
In response to this Jamie Raskin, a Democrat in the House of Representatives and the lead House impeachment manager, requested Mr Trump's testimony.
He said: "In light of your disputing these factual allegations, I write to invite you to provide testimony under oath, either before or during the Senate impeachment trial, concerning your conduct on January 6, 2021."
He asked that this happen between 8 and 11 February.
Mr Raskin added: "If you decline this invitation, we reserve any and all rights, including the right to establish at trial that your refusal to testify supports a strong adverse inference regarding your actions (and inaction) on January 6, 2021."
Watch: Donald Trump parts with lawyers a week before impeachment trial
In their written submission, Mr Trumps lawyers argued "It is denied that the phrase 'if you don't fight like hell you're not going to have a country anymore' had anything to do with the action at the Capitol as it was clearly about the need to fight for election security in general, as evidenced by the recording of the speech."
Mr Trump is the first president in history to be impeached twice.
With a two-thirds majority of the Senate needed to convict him, 17 Republican members of the upper chamber would have to vote with the Democrats against the previous commander-in-chief.
A simple majority of 51 would then be needed to stop Mr Trump from being able to ever hold office again.