The chairman of the House Intelligence Committee, Republican Mike Turner, issued an unusual statement this Wednesday in which he warned of a "serious threat to national security" White House National Security Advisor Jake Sullivan suggested shortly afterward in a press conference that he was perplexed by the congressman's statement because they had a briefing scheduled for Thursday. A Democratic source familiar with the threat told NBC News: “This is a serious matter that could lead to a destabilizing situation and a threat tonational security”