US President Donald Trump has named a new national security adviser to replace John Bolton.
Robert O'Brien has had a long career in foreign policy working for both main US parties and currently heads hostage negotiations at the State Department.
Mr. O'Brien is Mr. Trump's fourth national security adviser of his presidency.
He follows Mr. Bolton, H.R. McMaster and Michael Flynn in the role, which does not require confirmation by Congress.
As top adviser on national security, Mr. O'Brien will be tasked with tackling everything from immigration policy to heightened tensions with Iran.