"We said nothing", Mr Trump told reporters.
Fox News, known for its conservative opinions, nonetheless quickly denied that it had any reporting to support Trump's claim.
German Chancellor Angela Merkel and President Donald Trump met today after months of subtle jabs from Washington to Berlin.
President Donald Trump used a joint press conference with German Chancellor Angela Merkel to deflect criticism about his unsubstantiated claim that the Obama administration spied on him, reviving a sensitive diplomatic incident in which the US was revealed to have snooped on her cell phone.
The meeting, between two leaders who have not always agreed, is consequential for both sides.
A photo-op of the Oval Office meeting between the German Chancellor Angela Merkel and President Donald Trump ended on a slightly awkward note.
Trump's tax return got Rachel Maddow her highest ratings ever
David Cay Johnston , the editor and founder of dcreport.org, said he received Trump's tax information in the mail Monday. Trump says he has not released his tax returns because they are under audit by the Internal Revenue Service.
He is also expected to meet China's top diplomat, Yang Jiechi, and Xi. However, Ms Merkel did ask if he would like a handshake - an offer Mr Trump appeared to loftily ignore.
Donald Trump is once again chastising North Atlantic Treaty Organisation allies for not spending enough on defense, a somewhat troubling talking point of the president's that at one point led him to suggest the U.S. "That means the European Commission negotiates these free trade agreements". German Vice Chancellor Sigmar Gabriel later referred to Trump as "the pioneer of a new authoritarian and chauvinist worldwide movement".
Mr Trump said the United States would do "fantastically well" in its trade relations with Germany. But his recent snub at German Chancellor Angela Merkel just took the awkwardness to a whole new level.
"As far as wiretapping, I guess, by this past administration, at least we have something in common, perhaps", Trump said, drawing laughter. "We are trying to address the areas where we disagree....and find a compromise". And on Friday morning, United Kingdom prime minister Theresa May's official spokesman said that the Trump administration had promised never to make that allegation again. During his election campaign, Trump had frequently attacked Merkel for "ruining" Germany by allowing refugees and migrants from Syria to enter the country.
It's a sharp contrast from the relationship between Merkel and Trump's predecessor. "These nations must pay what they owe".
"This is obviously what we have an exchange of views about", she said.