Twitter briefing to U.S. congressional investigators disappointing -Senator Warner

WASHINGTON (Reuters) - U.S. Senator Mark Warner, top Democrat on the Intelligence Committee, said on Thursday he was deeply disappointed by the lack of information Twitter provided at a briefing for congressional investigators probing Russian interference in the U.S. election. He said the Twitter briefing was mostly derivative of a presentation earlier this month given by Facebook and lacked thoroughness. "Their response was, frankly, inadequate on almost every level," Warner told reporters. (Reporting by Dustin Volz; Writing by Eric Beech; Editing by Eric Walsh)