House Intelligence Committee Chairman Adam Schiff (D-CA), still licking his wounds from getting grounded by President Trump last week, has vowed to "absolutely" investigate a BuzzFeed News report that President Trump directed his former personal attorney to lie to Congress about a potential Trump Tower Moscow project that never materialized - despite special counsel Robert Mueller's office claiming the report is untrue.

"Absolutely. Absolutely," Schiff told CBS's "Face The Nation" after being asked whether he would investigate the allegations.

"Congress has a fundamental interest in two things. First, getting to the bottom of why this witness came before us and lied, and who else was knowledgeable that this was a lie," Schiff added.

The California Democrat also suggested that Mueller disputed the BuzzFeed report because he might want to use Cohen as a witness in future prosecutions, and "wanted to make sure that the public didn't have the perception that he was saying more than he was saying, at least to the special counsel."

Schiff says Mueller's office may have disputed BuzzFeed report because it wants to use Michael Cohen as witness for more prosecutions, and "wanted to make sure that the public didn't have the perception that he was saying more than he was saying, at least to the special counsel" pic.twitter.com/VqkmBY5Zkd — CBS News (@CBSNews) January 20, 2019

BuzzFeed, meanwhile, has doubled down after editor-in-chief Ben Smith and reporter Anthony Cormier both stood behind their reporting in a Sunday interview with CNN.

"I have further confirmation that this is right. We are being told to stand our ground. Our reporting is going to be borne out to be accurate, and we’re 100 percent behind it," Cormier told CNN's Brian Stelter, adding "The same sources that we used in the story are standing behind it, and so are we."

That said, Cormier deflected when asked about documents that his colleague, Jason Leopold, said he had seen while formulating the report. He was also hazy on what Cohen specifically told Mueller's team, or what Trump allegedly told Cohen.