(CNN) A Democratic senator who questioned Attorney General Jeff Sessions on Tuesday said he thinks Sessions' refusal to answer some questions suggests there is a "concerted effort" from the administration to obstruct the investigation into Russian interference in the 2016 election.
At Tuesday's hearing, New Mexico Democratic Sen. Martin Heinrich told Sessions he was "impeding" the congressional investigation by not answering questions.
"I have deep concerns any time a sitting attorney general refuses to answer questions under oath, and the attorney general refused time and time again, without ever invoking executive privilege," Heinrich said on CNN's "Erin Burnett OutFront." "He seemed to invent a brand new legal standard of 'appropriateness.' This is not a backyard barbecue. You either answer the question under oath, or you invoke executive privilege."
Sessions said during the hearing that it would be "inappropriate" for him to discuss details of private conversations with President Donald Trump. He did not claim executive privilege, but he did say that by not answering questions he was protecting the President's right to later invoke executive privilege "if he chooses." Sessions also cited Justice Department "longstanding policy" in explaining why he would not answer questions.
During his questioning, Heinrich said to Sessions, "Your silence speaks volumes."
"I walked away from this being highly concerned that there now seems to be a concerted effort by the administration to obstruct this investigation," Heinrich said on "OutFront." "He wouldn't answer the most basic question under oath. And we're not going to be able to get to the bottom of this matter if we don't have honest answers from the administration."
Asked if he believes Sessions' claims that he could not remember a third meeting with Russian Ambassador to the US Sergey Kislyak, Heinrich said he wants to see where the investigation goes.
"Certainly, if it was just a sort of pleasantries, and there were a number of people together, that would not constitute collusion. But the question is, why didn't he report that along with the other meetings?" he said. "I think if I had had a meeting with Ambassador Kislyak, or three for that matter, I would go the extra mile to make sure that every time I connected with him I was transparent about that with the US Congress."