Michael Cohen, attorney for The Trump Organization, arrives at Trump Tower in New York City, U.S. January 17, 2017.

House Intelligence Committee Chairman Adam Schiff, D-Calif., said Friday that his committee will increase its efforts to investigate an aborted Trump Tower Moscow deal in light of a bombshell report alleging President Donald Trump directed his ex-lawyer Michael Cohen to lie in sworn testimony to Congress.

That report, published Thursday night by BuzzFeed News, cites two federal law enforcement sources who also allege that Trump supported Cohen's plan for him to meet Russian President Vladimir Putin during the 2016 campaign to discuss the Trump Tower proposal.

Other outlets, including NBC News and CNBC, have not confirmed BuzzFeed's report.

"These allegations may prove unfounded, but, if true, they would constitute both the subornation of perjury as well as obstruction of justice," Schiff said in a statement released by a spokesman Friday morning.

"Our committee is already working to secure additional witness testimony and documents related to the Trump Tower Moscow deal and other investigative matters," Schiff said. "As a counterintelligence concern of the greatest magnitude, and given that these alleged efforts were intended to interfere with our investigation, our Committee is determined to get to the bottom of this and follow the evidence wherever it may lead."

BuzzFeed also cites "multiple witnesses from the Trump Organization and internal company emails, text messages, and a cache of other documents" related to Trump's reported directive that were found by special counsel Robert Mueller's team of investigators.

The White House dismissed the report. "I'm not going to give any credence" to Cohen, "who's a convicted liar," White House spokesman Hogan Gidley told Fox News on Friday. Trump's lawyer, former New York Mayor Rudy Giuliani, told The Washington Post that "if you believe Cohen, I can get you a great deal on the Brooklyn Bridge."

Late Friday, a spokesman for special counsel Robert Mueller disputed elements of the report in a statement to CNBC.

"BuzzFeed's description of specific statements to the Special Counsel's Office, and characterization of documents and testimony obtained by this office, regarding Michael Cohen's Congressional testimony are not accurate," Peter Carr said in a statement to CNBC.

Schiff has emerged as one of Trump's chief critics in Congress and has established himself as a watchdog on the president from his prior role as the intelligence committee's ranking Democrat. After BuzzFeed published its report, Schiff said that the allegation that Trump "may have suborned perjury" was "among the most serious to date."

Schiff tweet

In November, Cohen admitted lying to Congress about details surrounding the failed Trump Tower Moscow deal as part of a plea deal with Mueller, who is investigating Russia's election interference and possible collusion with the Trump campaign in the 2016 election.

Cohen has since cooperated extensively with Mueller's probe, court filings show.

Months earlier, Cohen had pleaded guilty to separate charges lodged by federal prosecutors in New York. He directly implicated Trump in his crimes when he admitted his involvement in hush-money payments made to two women who claim they had affairs with Trump years before he ran for president.

Trump tweeted Friday morning that Cohen was "lying to reduce his jail time!" without directly referencing BuzzFeed's report.

Trump tweet

Other Democratic leaders have weighed in on the report.

"Directing a subordinate to lie to Congress is a federal crime. The @HouseJudiciary Committee's job is to get to the bottom of it, and we will do that work," said House Judiciary Committee Chairman Jerry Nadler, D-N.Y., in a tweet.

Nadler tweet

When asked whether the tweet confirms that the Judiciary Committee is investigating the allegations made in BuzzFeed's report, a spokesman for Nadler told CNBC: "That is not what we said. We said we would be investigating obstruction of justice."

A spokesman for House Oversight Committee Chairman Elijah Cummings, D-Md., did not say if the Democratic leader plans to follow Schiff's lead. But he referred CNBC to prior press releases announcing that Cohen would be testifying before that committee on Feb. 7.

Sen. Richard Blumenthal, D-Conn., urged Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., to bring Cohen before the committee to testify.

"Our committee must conduct a thorough investigation of the President's involvement in these crimes and whether he obstructed justice to hide them," Blumenthal wrote in a letter to Graham.