The former director of the CIA and ex-defence secretary has hit out at US President Donald Trump for tweeting allegations without evidence.

Leon Panetta was responding to claims made by Trump on social media that accused former president Barack Obama of wiretapping him during the election campaign.

In an interview with CNN, Panetta said: "I mean this is the president of the United States and he has a responsibility to speak the truth to the American people.

"When he engages in these kinds of tweets and throws out these kinds of allegations, I think he weakens the office of the presidency."

In a series of tweets on Saturday (3 March), Trump wrote: "How low has President Obama gone to tapp my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!

"I'd bet a good lawyer could make a great case out of the fact that President Obama was tapping my phones in October, just prior to Election!"

A spokesperson for Obama denied the claims, which Trump has so far not backed up with any evidence.

It has been suggested by some Democrats including House Minority Leader Nancy Pelosi that Trump was attempting to provide a distraction amid suggestions members of his administration had links with Russia during the presidential election.

U.S. Defense Secretary Leon Panetta
Former defense secretary Leon Panetta.

Panetta added in the interview: "I sense that the White House is in a bunker mentality in which they think everybody is against them and the president feeling that way is now tweeting out anything he wants to say."