President Donald Trump on Wednesday stood by his explosive claim that Barack Obama ordered a wiretap of Trump Tower during the 2016 presidential campaign.

In what were his first comments on the scandal since he made the accusations in a series of tweets on March 4, the president told Fox News he expected "some very interesting items coming to the forefront over the next two weeks".

In excerpts of the interview, to be broadcast in full on Wednesday night, he also said that "wiretap covers a lot of different things".

Mr Trump has been under mounting pressure to provide evidence for the claims that his predecessor ordered a spying operation to be carried out on him in the run-up to November's election.

Devin Nunes, the Republican chairman of the House of Representatives Intelligence committee directly contradicted the president on Wednesday, saying: "We don't have any evidence that that took place."

"I don't think there was an actual tap of Trump Tower," he said. If Mr Trump's s tweets were taken literally, then "clearly the president was wrong".