President Donald Trump has stood by claims he was wiretapped under Barack Obama, telling visiting German Chancellor Angela Merkel: "At least we have something in common, perhaps."
US intelligence agencies under Obama reportedly monitored Merkel's phone, sparking an angry response.
But both Republican and Democratic congressional leaders have said they do not believe Trump was wiretapped.
Trump and Merkel have discussed key issues including Nato and trade.
Her visit had been scheduled for Tuesday but was postponed due to a snowstorm.
Trump made his wire-tapping jibe in a joint press conference with Merkel. She gave a quizzical look.
He
by White House press secretary Sean Spicer that the UK's GCHQ spy agency had carried out wiretapping on Trump during the US election campaign.
Trump said
Spicer had been quoting a comment on Fox TV. The president said he had not offered an opinion on it, adding: "You shouldn't be talking to me, you should be talking to Fox."
Fox later read out a statement on air, saying: "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."
GCHQ rejected the allegations against it as "nonsense" and Downing Street says it has been assured the US will not repeat the claims.
The US president was also asked if he regretted any of his regular tweets. He said "very seldom", adding that it was a way to "get round the media when it doesn't tell the truth".
The body language was at times awkward. In an earlier photo opportunity in the White House, Merkel asked him quietly: "Do you want a handshake?" He looked forwards with his hands clasped and did not reply.
The US president and the German chancellor were standing on the same stage, but it often seemed they inhabited different political universes.
Donald Trump, once again, focused on the issues that he campaigned on - issues, he is quick to remind reporters, that won him the presidency. He was quick to talk about "fair" trade, immigration control, military strength and manufacturing jobs.
Angela Merkel, on the other hand, focused on the benefits of globalism, openness to refugees and the need to negotiate a "safe and secure solution for Ukraine".
Leaders find their way into politics "on different pathways", as Merkel pointed out, and that was clearly the case at the White House on Friday afternoon.
The fast-talking Merkel, steeped in policy details, stood in stark contrast to the staccato Trump, who once again railed against unfair treatment at the hands of foreign trade negotiators and the domestic media.
Somehow these two very different individuals will have to find a way to work together on issues of global importance. This face-to-face meeting - complete with non-handshake and awkward body language - will likely prove to be only a tentative first step.