(CNN) The Senate intelligence committee has been in "constant contact" with the legal team of George Papadopoulos, the Trump campaign foreign policy adviser who has pleaded guilty to making a false statement to the FBI, the committee's chairman told reporters on Tuesday.

Going into a Senate intelligence hearing, Republican Sen. Richard Burr of North Carolina would not comment on Papadopoulos except to say his investigation and that of Justice Department special counsel Robert Mueller's are "in two different lanes." He said Papadopoulos was on their radar and that they had "constant contact with his legal team," along with the lawyers for former Trump campaign chairman Paul Manafort and his deputy, Rick Gates, who pleaded not guilty Monday after they were indicted.

"I don't think the indictments were a surprise to any of us who had been involved in the investigation for nine months," Burr said. "Does it make our job tougher? Only in the fact that there may be some information that we could get from Manafort or Gates that were not going to be able to get now because of the indictment. But we had assumed for quite a while that at some point they would be taken off the deck for us."

The Senate intelligence committee has not interviewed Papadopoulos, whose guilty plea for la source familiar with the matter told CNN on Monday. The House intelligence committee also has not spoken with him, according to a source.

The House intelligence committee also has not spoken with him, CNN also reported. The Senate panel had made an effort to secure an interview with Papadopoulos, the source said, and the committee's Russia investigators have viewed the emails that were included in the court documents unsealed.

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