Rep. Adam Schiff, D-Calif., said President Trump participated in illegal activity while he was president if the testimony by Trump’s former personal attorney Michael Cohen proves true.

“If Mr. Cohen’s allegations are correct, it means the president, while in office, literally while in the Oval Office was engaged in criminal activity, and that is furthering this campaign fraud scheme,” Schiff, chairman of the House Intelligence Committee, said during an interview with CNN Wednesday morning.

“So, that’s pretty breathtaking when you think about it, that the president of the United States is allegedly paying hush money as president of the United States, and misleading the country about it.” Schiff said. “And that’s pretty serious business.”

[Watch: Michael Cohen testifies before House Oversight Committee]

Cohen, who appeared before the House Oversight Committee on Wednesday, pleaded guilty to campaign finance violations regarding hush-money payments made during the 2016 campaign to two women who claimed they were involved in affairs with Trump. Cohen claimed that Trump was aware of the payments and told the panel he was reimbursed by Trump for the hush-money payments while Trump was president.

A check for $35,000 that was dated on Aug. 1, 2017 — one of several reimbursement installments — was displayed for lawmakers at the hearing.

“This $35,000 check was one of 11 check installments that was paid throughout the year while he was president,” Cohen said Wednesday.

“The president of the United States thus wrote a personal check for the payment of hush-money as part of a criminal scheme to violate campaign finance laws,” he said.

Cohen, who is set to begin a three-year prison sentence in May, appeared privately before the Senate Intelligence Committee on Tuesday. He will also appear before the House Intelligence Committee behind closed doors on Thursday.