Washington (CNN) White House press secretary Sarah Sanders said Thursday that she could not "verify the validity" of an NBC report that President Donald Trump's longtime personal lawyer Michael Cohen was wiretapped by federal investigators.

Sanders declined to say during a press briefing whether the President was concerned by NBC's reporting, saying, "I haven't talked to him about that," and adding, "I can't verify the validity of that report at this point."

"I would refer you to the President's outside counsel about any concerns of wiretapping," she said, and later referred a reporter to the Justice Department in response to a question about whether the department authorized a wiretap.

During the briefing, Sanders said she was unsure of when Trump and Cohen last spoke, and said she is "not aware of specific" matters where Cohen is representing the President.

NBC News reported Thursday that Cohen was wiretapped, citing two people with knowledge of legal proceedings related to Cohen.

Read More