Senators on Tuesday described the testimony of Michael Cohen, the president's former personal attorney and fixer, as an "extensive grilling," but refrained from divulging details about the first of three highly anticipated congressional hearings this week.
"Cohen was serious," Sen. Roy Blunt, R-Mo., told reporters. "Focused, at least initially, on a number of things that Mr. Cohen had said that turned out not to be true. There were lots of questions to be asked."
Another Republican on the panel, Sen. Susan Collins of Maine, characterized Tuesday's hearing as an "extensive grilling" and described Cohen as a "very different guy."
Departing after more than nine hours of closed-door testimony, Cohen ignored reporters' questions, but offered gratitude for the opportunity to speak his piece.
"At this point in time I really appreciate the opportunity to clear the record and tell the truth," Cohen told reporters Tuesday night. "I look forward to tomorrow -- let American people decide exactly who's telling the truth."
Cohen's truth could carry dire implications for President Donald Trump, a man he worked alongside for more than a decade. Emerging from the interview room, the top Democrat on the committee, Sen. Mark Warner, D-Va., expressed alarm at what Cohen told the panel.
"Two years ago when this investigation started, I said it may be the most important thing I'm involved in in my public life in the senate and nothing I have heard today dissuades me from that view," Warner said.
The timing of Cohen's arrival on Capitol Hill coincided with the timing of another high-stakes event taking place on the other side of the globe. Trump touched down in Hanoi for his second summit with North Korean leader Kim Jong Un Tuesday morning just moments before Cohen was seen entering the committee room for his closed testimony.
The White House on Tuesday slammed congressional Democrats as "pathetic" for allowing Cohen to testify.
"Disgraced felon Michael Cohen is going to prison for lying to Congress and making other false statements," a statement from White House press secretary Sarah Sanders read. "Sadly, he will go before Congress this week and we can expect more of the same. It's laughable that anyone would take a convicted liar like Cohen at his word, and pathetic to see him given yet another opportunity to spread his lies."
Cohen's testimony on Tuesday marked the first of three highly anticipated hearings this week.
After his closed hearing to the Senate panel on Tuesday, Cohen will make his way across Capitol Hill to the House of Representatives on Wednesday, where he will testify in public for the first time before the House Oversight Committee.
ABC News reported Tuesday that when Cohen takes the stand Wednesday, he will for the first time publicly accuse President Donald Trump of potentially committing a crime while in office, according to a source familiar with his intended testimony.
The accusation, according to the source, is related to Trump's alleged repayment of money to Cohen for a hush money deal with Stormy Daniels, the adult film actress and director who claims to have had an affair with Trump. Trump has denied Daniels' claim but has admitted to the reimbursement. The source told ABC News that Cohen is expected to show the panel a signed check.
Additionally, the source said Cohen is expected to make public some of Trump's private financial statements that allege he -- at times -- inflated or deflated his net worth for business or personal purposes, including avoiding paying property taxes. ABC News has not reviewed the documents.
Asked Tuesday morning whether she had a reaction to news that Cohen expects to implicate the president in possible criminal activity, House Speaker Nancy Pelosi, D-Calif., said, "We'll see what he says tomorrow."
Cohen will finish his trio of congressional hearings on Thursday before the House Intelligence Committee in another closed door hearing.
The longtime fixer for Trump pleaded guilty in November to lying to Congress about a Trump Tower project in Moscow that the president's real estate company was pursuing at the same time he was running for president in 2016.
In statements to the House and Senate Intelligence committees, Cohen testified the project ended in Jan. 2016. He later said it continued well into the campaign, at least until June of that year.
Cohen is scheduled to report to prison in early May for a three-year sentence.
ABC News' Mary Bruce, Sarah Kolinovsky, Allison Pecorin, Mariam Khan and Trish Turner contributed reporting.
Senators describe Michael Cohen's 'extensive grilling,' but offer few details