Donald Trump has refused to back down over his claim that former president Barack Obama ordered surveillance of him during last year's election campaign.

The US president has spoken for the first time about the allegations he made in a Twitter rant earlier this month.

In the tweets, he wrote "Terrible! Just found out that Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism!"

Trump went on to say Obama was a "bad (or sick) guy".

Image: Donald Trump speaking at a rally in Nashville on Wednesday

The White House has yet to provide any evidence to support Trump's claims and the Department of Justice has asked for more time to respond to requests for proof from congressional investigators.


But in an interview with Fox News Channel's Tucker Carlson Tonight, Trump said: "We have a lot right now."

He said he might be addressing the controversy next week and added: "When I say wiretap, those words were in quotes, wiretapping is pretty old fashioned stuff, that really covers many other things.

"I think you are going to find some very interesting items coming to the forefront over the next two weeks."

But his comments came a few hours after the Republican and Democratic leaders of the House of Representatives' Intelligence Committee said they had seen no evidence to support the claim.

Image: Earlier on Wednesday, Mr Trump laid a wreath at the tomb of former president Andrew Jackson

Under US law, the FBI would need to obtain a warrant from an intelligence court to conduct surveillance operations. It would have to demonstrate just cause to persuade a judge.

FBI director James Comey is due to appear at an open session on Capitol Hill on Monday to answers questions from members of Congress about allegations of Russian interference in the presidential election.

It is unrelated to the investigation and indictment of Russian spies by the Department of Justice for the alleged hack of 500 million Yahoo customers.

In the Fox News interview, Trump said he had "no idea" how parts of his tax return from 2005 were leaked to an investigative reporter, denying it was released by the White House.

When Trump got it wrong. . . and right

But the president, who has broken with US political precedent in refusing to release his tax returns, called the leak "illegal" and a "disgrace".

Trump also defended his use of Twitter as a way of bypassing what he describes as unfair coverage in the mainstream media.

He also promised again to deliver on his promise to repeal and replace Obamacare, despite growing opposition on Capitol Hill to the current plan under discussion.

The Trump administration will today reveal details of its first budget with major cuts expected to the State Department and Environmental Protection Agency.