Donald Trump Picks James Mattis for Defense 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 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.

"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 Kimberley Halkett reported from Cincinnati.

Mattis, whose past assignments include leading Central Command, which oversees US military operations in the Middle East and South Asia, is known for his colorful 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.