Democratic House Speaker Nancy Pelosi invited President Donald Trump to testify in front of investigators in the House impeachment inquiry ahead of a week that will see several key witnesses appear publicly.

Pushing back against accusations from the president that the process has been stacked against him, Pelosi said Trump is welcome to appear or answer questions in writing, if he chooses.

“If he has information that is exculpatory, that means ex, taking away, culpable, blame, then we look forward to seeing it,” she said in an interview that aired Sunday on CBS’s “Face the Nation.” Trump “could come right before the committee and talk, speak all the truth that he wants if he wants,” she said.

And he recounted that Sondland told a top Ukrainian official in a meeting that the vital US military assistance might be freed up if the country’s top prosecutor “would go to the mike and announce that he was opening the Burisma investigation.” Burisma is the gas company that hired Hunter Biden.

Morrison’s testimony contradicted much of what Sondland told congressional investigators during his own closed-door deposition, which the ambassador later amended.

“If Donald Trump doesn’t agree with what he’s hearing, doesn’t like what he’s hearing, he shouldn’t tweet. He should come to the committee and testify under oath. And he should allow all those around him to come to the committee and testify under oath,” Schumer told reporters. He said the White House’s insistence on blocking witnesses from cooperating begs the question: “What is he hiding?”

Multiple witnesses overheard a phone call in which Trump and Sondland reportedly discussed efforts to push for the investigations. In private testimony to impeachment investigators made public Saturday, Tim Morrison, a former National Security Council aide and longtime Republican defense hawk, said Sondland told him he was discussing Ukraine matters directly with Trump.

Trump has said he has no recollection of the overheard call and has suggested he barely knew Sondland, a wealthy donor to his 2016 campaign. But Democrats are hoping he sheds new light on the discussions.

“I’m not going to try to prejudge his testimony,” Rep. Jim Himes, D-Conn., said on “Fox News Sunday.” But he suggested, “it was not lost on Ambassador Sondland what happened to the president’s close associate Roger Stone for lying to Congress, to Michael Cohen for lying to Congress. My guess is that Ambassador Sondland is going to do his level best to tell the truth, because otherwise he may have a very unpleasant legal future in front of him.”