By Jeff Mason and Mark Hosenball
WASHINGTON (Reuters) - U.S. President Donald Trump stood by unproven claims on Friday that the Obama administration tapped his phones during the 2016 White House race and shrugged off a dispute with Britain over the notion their spy agency had a hand in it.
British Prime Minister Theresa May's spokesman earlier in the day dismissed the charge against Britain's GCHQ spy agency as "ridiculous" and said the White House had promised not to repeat it.
But at a news conference Trump brushed aside a question about whether it was a mistake to accuse British intelligence of eavesdropping.
"We said nothing. All we did was quote a certain very talented legal mind who was the one responsible for saying that on television. I didn't make an opinion on it," Trump said.
He was referring to Fox News analyst Andrew Napolitano who on Tuesday accused Britain's Government Communications Headquarters (GCHQ) intelligence agency of having helped Obama, a Democrat, wiretap Trump, a Republican.
White House spokesman Sean Spicer on Thursday quoted Napolitano's comments about GCHQ during a testy briefing with reporters.
But speaking at the White House news conference, with German Chancellor Angela Merkel, at his side, Trump distanced himself.
"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. OK?" Trump said while standing by his initial charge that the previous U.S. administration eavesdropped on him.
"As far as wiretapping, I guess by this past administration, at least we have something in common, perhaps," he said to Merkel.
U.S. ties with Germany were frayed by news reports in 2013 citing leaked intelligence documents that Washington had bugged Merkel's mobile phone.
A White House official, speaking on condition of anonymity, said British officials had voiced concern to senior Trump aides but the official declined to explicitly apologise for Spicer's citation of the Fox News allegations.
The Republican Trump, president since Jan. 20, tweeted this month that his Democratic predecessor had wiretapped him during the late stages of the 2016 campaign. Trump offered no evidence, and an Obama spokesman has said the claim is "simply false".
Leaders of both major parties in Congress have joined a growing chorus disputing it.
On Friday, the U.S. Justice Department said it had responded to a request by committees in Congress for documents that could shed light on Trump's claim.
A government source, who requested anonymity when discussing sensitive information, said an initial examination indicated it contained no evidence to support Trump's charge.
On the "Fox & Friends" program, Napolitano, a political commentator and former New Jersey judge, said that rather than ordering U.S. agencies to spy on Trump, Obama had obtained transcripts of Trump's conversations from GCHQ so there were "no American fingerprints" on it.
Late on Friday, Fox News anchor Shepard Smith said: "Fox News cannot confirm Judge Napolitano's commentary. Fox News knows of no evidence of any kind that the now president of the United States was surveilled at any time in any way, full stop.”
Dominic Grieve, chairman of the British Parliament's Intelligence and Security Committee, said a U.S. president cannot task the GCHQ to intercept an individual's communications.
In a rare public statement, the GCHQ, Britain's equivalent of the U.S. National Security Agency which monitors overseas electronic communications, said the claims should be ignored.
Reuters reported earlier this week that an unidentified British security official had denied the allegations about Trump.
GCHQ, based in western England, is one of three main British spy agencies alongside the MI6 Secret Intelligence Service and the MI5 Security Service.
(Additional reporting by Elizabeth Piper, Michael Holden and Guy Faulconbridge in London; Writing by Howard Goller; Editing by Mary Milliken)