Rep. Adam Schiff (D-Calif.) said Wednesday that the House Intelligence Committee has an "abundance" of information that is not yet public, including evidence that President Trump's campaign colluded with Russia and that his administration obstructed justice.

"There is certainly an abundance of non-public information that we've gathered in the investigation. And I think some of that non-public evidence is evidence on the issue of collusion and some ... on the issue of obstruction," Schiff said, according to The Guardian.

Schiff, who is the ranking Democrat on the House Intelligence Committee, said the panel has seen evidence of money laundering, but has been unable to further investigate.

"As a former prosecutor, you follow the money. We have not been able to adequately follow the money," Schiff said.

The House Intelligence Committee is one of multiple congressional committees leading separate investigations into Russian meddling in the 2016 election.

Special counsel Robert Mueller is leading a criminal investigation into the same subject, which has thus far resulted in two indictments and two guilty pleas.

Schiff has frequently sparred with Trump as the investigation progresses.

After Trump allowed the release of a Republican memo accusing the FBI of surveillance abuses, Schiff said the president was using the Justice Department as a "political tool."

Schiff has sought the release of a Democratic countermemo, but Trump blocked its release last week. Schiff has vowed not to revise the document, despite White House requests to do so.