Washington, Dec 2 (IANS): US President-elect Donald Trump has chosen retired Marine General James N. Mattis to be his Secretary of Defense, reports said on Friday.

The US President-elect announced his choice at a rally on Thursday, but the official announcement is expected to be on Monday, reported the Washington Post.

Trump picked the former senior military officer who had said that responding to "political Islam" was "the major security issue facing the US".

"We are going to appoint 'Mad Dog' Mattis as our secretary of defense," Trump told in a rally in Cincinnati, his first stop after the November 8 election, also his "thank-you tour".

Trump joked that the media and audience should keep the news to themselves. "We are going to be announcing him Monday of next week," Trump said. "Keep it inside the room".

Mattis, who retired as chief of the US Central Command in 2013, has often said that Washington lacks an overall strategy in the Middle East, opting to instead handle issues in an ineffective one-by-one manner.

"Is political Islam in the best interest of the US?" Mattis said at the Heritage Foundation in 2015, speaking about the separate challenges of the Islamic State (IS) and Iranian-backed terrorism.

"I suggest the answer is no, but we need to have the discussion. If we won't even ask the question, how do we even recognise which is our side in a fight?" he had said.

To take the job, Mattis will need Congress to pass legislation to bypass a federal law stating that defense secretaries must not have been on active duty in the previous seven years.

Congress had granted a similar exception just once, when General George C. Marshall was appointed to the job in 1950.