The newly appointed interim national security adviser is preparing to stay in that role for up to six months, a person close to him said.

U.S. President Donald Trump ousted his national security adviser Mike Waltz on Thursday and named Secretary of State Marco Rubio as his interim replacement in the first major shakeup of Trump's inner circle since he took office in January.

President Trump's top policy adviser, Stephen Miller, is garnering buzz inside the White House as a top candidate to be the next national security adviser, five sources familiar with the situation say.