Washington (CNN) Virginia Democratic Sen. Mark Warner said on CNN's "State of the Union" that KT McFarland, a former Trump transition official and deputy national security adviser, needs to provide testimony to Congress and special counsel Robert Mueller.

"Ms. McFarland needs to come in, and not just testify in front of Mueller, but testify in front of the congressional committees," Warner said Sunday.

The comments from Warner, as well as his colleague, California Democratic Sen. Dianne Feinstein, indicate that new reports are putting increased scrutiny on McFarland -- and that congressional investigations into potential obstruction by the White House are moving forward.

Feinstein also said that McFarland needed to testify while on NBC's "Meet the Press."

Warner, the Senate Intelligence Committee's ranking member, said he and North Carolina Republican Sen. Richard Burr, who chairs the committee, continued to work effectively on their investigation into alleged Russian interference in the 2016 election and potential coordination with President Donald Trump's associates.

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