John Bolton, the former U.S. ambassador to the United Nations, will replace H.R. McMaster as national security adviser, President Donald Trump announced in a tweet.

Bolton, who served in the George W. Bush administration, is known for his hard-line foreign policy views, and has written in support of attacking North Korea. McMaster’s exit is just the latest in a long line of departures from the Trump White House. Trump had been preparing to replace McMaster for weeks, NBC News has reported.

Source: NBC News