US president-elect says he will appoint a retired general renowned for his tough talk as defense secretary.

President-elect Donald Trump has said he will nominate retired Marine Corps General James Mattis to be his defense secretary.

Mattis, who is known as “Mad Dog” and renowned for his tough talk, retired in 2013 after serving in Iraq and Afghanistan.

James Mattis, 66, ex-Marine 2010-2013: Led the Central Command, which oversees US military operations in the Middle East and South Asia

2005: He was quoted as saying: it was “fun to shoot some people”

2004: Leader of Marines in battle of Fallujah in Iraq

2003: Helped lead the invasion into Iraq

2001: Invasion of Kandahar province in Afghanistan

1991: Was part of an assault battalion into Kuwait during the first US war with Iraq

1972: Commissioned as an officer

1969: Enlisted in the Marine Corps

1950: Born in Pullman, Washington state

If confirmed, Mattis would be the second retired general to serve as defense secretary

“We are going to appoint ‘Mad Dog’ Mattis as our secretary of defense,” Trump announced during a post-election victory rally in Cincinnati on Thursday. He said the formal announcement would be made on Monday.

His appointment 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 has often been very critical of Washington, especially when it comes to the strategy in the Middle East, saying the US simply has no strategy,” Al Jazeera’s Kimberly Halkett reported from Cincinnati.

Halkett said Mattis is “known to have a rather aggressive stance against former adversaries, particularly Iran” and is not supportive of the Iran nuclear agreement.

“He says it [the Iran deal] may slow but certainly not stop Iran from obtaining a nuclear weapon,” she said.

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.

“It will be difficult to get Mattis approved [by Congress] given the fact there is currently a law that says any secretary of defense should not have been in active duty in the past seven years,” Halkett added.

“Certainly Trump feels that this is something that can be overlooked.”

Congress can make an exception for Mattis, as it did for George C Marshall in 1950.