US President Donald Trump repeats his accusation that former President Barack Obama had ordered intelligence agencies to spy on him.

Speaking at a joint press conference with German Chancellor Angela Merkel on Friday, Trump said he and Merkel might find common ground over allegations of wiretapping by the Obama administration.

"As far as wiretapping, I guess, by this past administration, at least we have something in common perhaps," Trump said.

The US National Security Agency spied on the last three German chancellors and their offices for decades, according to the whistleblower website WikiLeaks.

The leaked WikiLeaks documents have suggested that the NSA spooked on Angela Merkel, Gerhard Schroder, and Helmut Kohl.   

Earlier this month, Trump accused his predecessor of intercepting his communications at his offices in Trump Tower in New York City just before the November presidential election.

On Thursday, the White House accused Britain's GCHQ intelligence agency of tapping Trump Tower for Obama during the election campaign.

Trump however said on Friday he did not endorse claim that the British spy agency did the wiretapping for Obama. "We said nothing" about the GCHQ claim, Trump told reporters.

"That was a statement made by a very talented lawyer on Fox. And so you shouldn't be talking to me, you should be talking to Fox," he said.

Meanwhile, reports say the US Congress has found no evidence that proves the Obama administration wiretapped Trump during his election campaign.

Heads of intelligence committees in the House of Representatives and the Senate have reportedly come to the conclusion after initial examination of information provided by the Justice Department.

The Congress had requested copies of any court order related to Trump or his associates. Congressmen sought to find any order issued under surveillance or anti-crime regulations.

Trump is under pressure from both Republicans and Democrats to withdraw the accusations and apologize.