A US House select committee investigating the January 6 riot is asking former President Donald Trump's daughter and then-senior White House adviser Ivanka Trump to cooperate with its investigation.

Iran PressAmerica: The committee publicly released a letter dated Thursday addressed to Ivanka Trump seeking "voluntary cooperation with our investigation." In the letter, the committee revealed explosive new details about the former President's actions in the days leading up to and on January 6.

The letter included new testimony about Trump's efforts to pressure former Vice President Mike Pence to bend to his will on the morning of January 6, as well as new text messages from Fox host Sean Hannity -- in the aftermath of the attack, texts that urged the White House to get Trump to stop talking about the election being stolen and to distance the former President from certain "crazy people."

The invitation to Ivanka is the first time the committee has sought testimony from a member of the President's family, in the latest sign that the panel is closely scrutinizing the actions of the President and those around him before, during, and after January 6.

The outreach to Ivanka Trump comes after CNN reported earlier this week that the committee had subpoenaed and obtained call records from Eric Trump and Kimberly Guilfoyle, who is engaged to Donald Trump Jr.The committee's decision to publicly seek Ivanka Trump's testimony comes a day after the Supreme Court cleared for the release of presidential records from the Trump White House through the National Archives.

The letter the committee sent to Ivanka provided additional detail showing what the committee has already uncovered -- and what it hopes to learn from Ivanka Trump.

The panel wrote that Keith Kellogg -- Pence's national security adviser who was with Trump in the White House when the riot was happening -- testified about how the former President attempted to coerce Pence during a phone call the morning of January 6. Ivanka Trump was present for Trump's end of the call.

In testimony to the committee, Kellogg reiterated that the former President told Pence, "You're not tough enough to make the call."Kellogg also corroborated an account of the phone call where Trump claimed that if Pence did not do what he was asking, he had selected the wrong running mate.

"Mike, it's not right. You can do this. I'm counting on you to do it. If you don't do it, I picked the wrong man four years ago. You're going to wimp out, "read the transcript of the interview that Kellogg confirmed.

Kellogg also revealed in his testimony to the committee that after the phone call ended, Ivanka Trump turned to him and said, "Mike Pence is a good man," to which Kellogg affirmed, "Yes, he is."

The panel is asking Ivanka Trump for her account of this conversation and any other ones she may have witnessed, in which, her father discussed plans to obstruct or impede the election certification process.

The committee also wants to learn more from Ivanka about her father's "state of mind" as the attack unfolded.