Update: Sen. Lisa Murkowski (R-AK) on Monday joined Sens. Mitt Romney (R-UT) and Susan Collins (R-ME) in expressing interest in hearing from former White House National Security Advisor John Bolton after the New York Times reported that a leak portion of his book claims President Donald Trump sought to tie aid to Ukraine to investigations.

“I stated before that I was curious as to what John Bolton might have to say. From the outset, I’ve worked to ensure this trial would be fair and that members would have the opportunity to weigh in after its initial phase to determine if we need more info,” she said in a statement. “I’ve also said there is an appropriate time for us to evaluate whether we need additional information —that time is almost here. I look forward to the White House wrapping up presentation of its case.”

Read Breitbart News’ original report below:

Sens. Mitt Romney (R-UT) and Susan Collins (R-ME) said Monday that, respectively, he believes it is “important” for former White House National Security Advisor John Bolton to testify in the Senate impeachment trial, and she thinks the leaks of Bolton’s upcoming book that may tie into the case “strengthen” the argument for calling him as a witness.

“I think with the story that came out yesterday, it’s increasingly apparent it would be important to hear from John Bolton,” Romney told reporters. “I, of course, will make a final decision on witnesses after we’ve heard from not only the prosecution but also the defense. But I think at this stage it’s pretty fair to say that John Bolton has a relevant testimony to provide to those of us who are sitting in impartial justice.”

Collins released a statement Monday that she is still in favor of witnesses at the trial. “The reports about Bolton’s book strengthen the case for witnesses and have prompted a number of conversations among my colleagues,” she said.

JUST IN: GOP Sen. Susan Collins: "The reports about John Bolton's book strengthen the case for witnesses and have prompted a number of conversations among my colleagues." https://t.co/kT4FAgq5Ad pic.twitter.com/UqRfU84P2o — ABC News (@ABC) January 27, 2020

Romney has previously signaled his support for calling additional witnesses as part of the upper chamber’s proceedings, including Bolton.

“I support the Clinton impeachment model, which is a vote on witnesses later. But as to which witnesses I’d want to hear from, and so forth, that’s something which I’m open to until after the opening arguments,” the Utah Republican said earlier this month.

Bolton is someone who “I would like to hear from, and presumably, I’d get the chance to vote for that,” he added.

In addition to Romney and Collins, Sens. Lisa Murkowski (R-AK), and Cory Gardner (R-CO) could also support hearing from Bolton. Sen. Lamar Alexander (R-TN), who will not run for re-election, may also back the move.

Earlier Monday, President Donald Trump rebuked claims that he sought to tie aid to Ukraine to inquiries into “Democrats,” tweeting:

…transcripts of my calls with President Zelensky are all the proof that is needed, in addition to the fact that President Zelensky & the Foreign Minister of Ukraine said there was no pressure and no problems. Additionally, I met with President Zelensky at the United Nations… — Donald J. Trump (@realDonaldTrump) January 27, 2020

…(Democrats said I never met) and released the military aid to Ukraine without any conditions or investigations – and far ahead of schedule. I also allowed Ukraine to purchase Javelin anti-tank missiles. My Administration has done far more than the previous Administration. — Donald J. Trump (@realDonaldTrump) January 27, 2020

The New York Times first reported on the allegations Sunday evening.

Romney’s remarks come as President Trump’s legal team is set to continue its opening arguments against the president’s removal.