Washington: US President-elect Donald Trump on Friday announced that he will nominate US Marine retired general James Mattis, who is renowned for his tough talk and battlefield experience in Iraq and Afghanistan, also known as ‘Mad Dog’,to be his defense secretary.

"We are going to appoint 'Mad Dog' Mattis as our Secretary of Defence," Trump told a cheering crowd at Cincinnati in Ohio in his first of the series of 'Thank You' victory tour.

"But we are not announcing this till Monday, so don't tell anybody," Trump told his supporters.

Trump described 66-year-old Mattis as "one of our great, great generals."

"He's our best. They say he's the closest thing to general George Patton that we have and it's about time," Trump said at the rally.

James Mattis commanded a Marine battalion during the First Gulf War and a Marine division during the 2003 invasion of Iraq. In 2010, he was named to head the US Central Command.

Tough-talking Mattis attracted controversy in 2005 when he said "it's fun to shoot some people" while addressing service members in San Diego.

If confirmed by the US Senate, Mattis would replace outgoing Defence Secretary Ashton Carter.

The nomination comes after Mattis met with Trump in Bedminster, New Jersey, last month.

Trump had said he changed his position on enhanced interrogation after meeting Mattis.

"General Mattis is a strong, highly dignified man. I met with him at length and I asked him that question. I said, What do you think of water boarding?" Trump told The New York Times in an interview.

"I was surprised that I have never found it to be useful.I have always found, give me a pack of cigarettes and a couple of beers and I do better with that than I do with torture," Trump said.