According to BuzzFeed News, Trump “personally instructed” Michael Cohen to lie to Congress in 2017 about a planned Trump Tower in Moscow, claiming negotiations ended months earlier than they actually had.

Trump repeatedly denied having business interests in Russia while on the campaign trail in 2016. And while Cohen already pleaded guilty to lying about the aforementioned deal in November, this is the first report that he did so at Trump’s behest.

The two unnamed law enforcement officials told BuzzFeed that Trump directed Cohen to lie to obscure his involvement in the deal. Trump and Cohen also reportedly had at least 10 face-to-face meetings about the deal during the campaign and Cohen provided “regular, detailed updates” to Ivanka and Donald Trump Jr.

Mueller’s office reportedly has evidence of this potential cover-up beyond just Cohen’s testimony. BuzzFeed reports that it is backed up by “interviews with multiple witnesses from the Trump Organization and internal company emails, text messages, and a cache of other documents.”

If the report is true, it could be the strongest indication that Trump sought to obstruct justice—a potentially impeachable offense. Leading Democrats are latching on, calling for an investigation.

Rep. Ted Lieu, for example, tweeted late Thursday, “This stunning Trump Tower Moscow story establishes a clear case of Obstruction of Justice, a felony. I’ve lost count now how many times @realDonaldTrump has engaged in Obstruction of Justice.

“Oh, fyi the first Article of Impeachment for Richard Nixon was Obstruction of Justice.”

This stunning Trump Tower Moscow story establishes a clear case of Obstruction of Justice, a felony. I've lost count now how many times @realDonaldTrump has engaged in Obstruction of Justice.

Oh, fyi the first Article of Impeachment for Richard Nixon was Obstruction of Justice. https://t.co/WjsdSAv7lR

— Ted Lieu (@tedlieu) January 18, 2019

Rep. Adam Schiff, tweeted that “The allegation that the President of the United States may have suborned perjury before our committee in an effort to curtail the investigation and cover up his business dealings with Russia is among the most serious to date. We will do what’s necessary to find out if it’s true.”

The allegation that the President of the United States may have suborned perjury before our committee in an effort to curtail the investigation and cover up his business dealings with Russia is among the most serious to date. We will do what’s necessary to find out if it’s true. https://t.co/GljBAFqOjh

— Adam Schiff (@RepAdamSchiff) January 18, 2019

Trump attorney Rudy Giuliani, meanwhile, appeared to write off the allegations, telling a number of media outlets on Thursday, “if you believe Cohen, I can get you a good all-cash deal on the Brooklyn Bridge.”

Cohen is due to publicly testify to the House Oversight Committee on Feb. 7.