Multiple sources (including the National Journal and Norah O'Donnell of NBC) are reporting that President Obama will give an impromptu televised statement TONIGHT at 10:30PM Eastern. The subject of the address has not been announced.
(This diary is obviously a shell and will be updated as the evening goes on.)
Let the speculation begin...
Live feed from the White House is available here.
UPDATE: CNN is reporting via Twitter that it's "national security related."