National Security Adviser to brief Congress on unspecified threat

White House National Security Adviser Jake Sullivan will brief Congressional leaders on an unspecified "serious" national security threat. The House Intelligence Committee chair called for the declassification of information related to the threat. Sullivan described the congressman's statement as unexpected and highly unusual. He declined to provide further details but emphasized the scheduled briefing. House Speaker Mike Johnson stated there is no reason for public alarm. The matter remains undisclosed.