US President-elect Donald Trump stands with retired Marine Gen. James Mattis following their meeting at the main clubhouse at Trump National Golf Club in Bedminster, New Jersey, US, November 19, 2016. [Photo/Agencies]

WASHINGTON - US President-elect Donald Trump said on Thursday he has chosen retired Marine General James Mattis for secretary of defense.

"We are going to appoint 'Mad Dog' Mattis as our secretary of defense. But we're not announcing it until Monday so don't tell anybody," Trump said at a rally in Cincinnati, kicking off his post-election "Thank You" tour.

"They say he's the closest thing to Gen. George Patton that we have and it's about time," he added.

Mattis, 66, known as "Mad Dog", retired as chief of US Central Command in 2013. He has often criticized Washington for lacking an overall strategy in the Middle East.