Bolton hires longtime adviser as deputy

Charles Kupperman, a longtime colleague of White House national security adviser John Bolton, to serve as his deputy

Bolton says in a statement that Kupperman has been an adviser to him for more than 30 years. He adds, "Charlie's extensive expertise in defense, arms control and aerospace will help further President Trump's national security agenda."

Kupperman, a former executive for defense contractors Boeing and Lockheed Martin, is the fourth person to hold the role under Trump.

Trump's administration has set records for turnover at all staff levels.