The top Democrat on the House Intelligence Committee said Wednesday he has "grave concerns" after House Intelligence Committee Chairman Rep. Devin Nunes shared information with President Trump that was withheld from his committee, and said Nunes' actions show that an independent commission is needed to investigate Trump's connections to Russia.

Nunes, R-Calif., said earlier that he had briefed Trump on new information, unrelated to an investigation into Russian activities, that suggested that several members of Trump's transition team and perhaps Trump himself had their identities "unmasked" after their communications were intercepted by U.S. intelligence officials. The revelation is notable because identities of Americans are generally supposed to remain "masked" if American communications are swept up during surveillance of foreign individuals.

During a press conference Wednesday afternoon, Rep. Adam Schiff, D-Calif., ranking member of the House Intelligence Committee, expressed his dismay about not being kept in the loop on this new information, which he said prevents the committee from evaluating the "merits" of the information Nunes shared.

Schiff also said the Nunes' meeting with Trump casts doubt on whether the chairman can continue to be an impartial head of any investigations related to Trump.

"The chairman will need to decide whether he is the chairman of an independent investigation into conduct which includes allegations of potential coordination between the Trump campaign and the Russians, or he is going to act as a surrogate of the White House because he cannot do both," Schiff said. "And unfortunately, I think the actions of today throw great doubt into the ability of both the chairman and the committee to conduct the investigation the way it ought to be conducted."

Schiff said he has expressed these "grave concerns" with Nunes, and pointed out that he is upset that Nunes shared the details of his meeting with the press before coming to the committee. He added that the incident underscores the need for an independent commission, which House Speaker Paul Ryan can initiate.

"I think it does underscore the importance of establishing an independent commission, a body that is fully independent of any political considerations including those that may emanate from the White House," Schiff said. "That would certainly give me a lot of confidence that in addition to whatever work our committee does and the Senate intelligence committee does, that there is a truly independent body that is looking into the grave issues that have been raised."