President-elect Donald Trump has said he would nominate retired General Marine Corps James Mattis to be his defence secretary.
Mattis, who is known as "Mad Dog" and renowned for his tough talk, retired in 2013 after serving in Iraq and Afghanistan.
"We are going to appoint 'Mad Dog' Mattis as our secretary of defence," Trump announced during a post-election victory rally in Cincinnati on Thursday. He said the formal announcement would be made on Monday.
The choice of a seasoned military strategist would be another indication that Trump, a Republican, intends to steer US foreign policy away from Democratic President Barack Obama's increased reliance on US allies to fight armed groups and to help deter Russian and Chinese aggression in Europe and Asia.
Mattis is a revered figure in the Marine Corps and known for his distrust of Iran.
Mattis, whose past assignments include leading Central Command, which oversees US military operations in the Middle East and South Asia, is known for his colourful expressions that unashamedly embrace the job of the US armed forces: fighting wars.