Trump taps Mike Pompeo lieutenant as new national security adviser

President Donald Trump has announced a new national security adviser.

The president abruptly fired John Bolton last week via tweet, and he tweeted out the announcement Wednesday morning of Robert O’Brien as a replacement.

"I am pleased to announce that I will name Robert C. O’Brien, currently serving as the very successful Special Presidential Envoy for Hostage Affairs at the State Department, as our new National Security Advisor," the president tweeted. "I have worked long & hard with Robert. He will do a great job!"

O'Brien has worked alongside Secretary of State Mike Pompeo, who had been considered for a dual role leading the national security council.

He also led an unsuccessful effort to free rapper ASAP Rocky from jail after he was arrested in Sweden on assault charges.