US President Donald Trump has named Lt Gen HR McMaster as his national security adviser.
He will replace Lt Gen Michael Flynn who was fired after just three weeks and three days in the job.
A lieutenant general with the US Army, HR McMaster served in Iraq and Afghanistan, where he worked on a government anti-corruption drive.
Mr Trump’s first choice, retired Vice Admiral Robert Harward, turned down the role, citing “personal reasons”.
Mr Trump has praised Herbert Raymond McMaster as “a man of tremendous talent and tremendous experience” who is “highly respected by everybody in the military”.