America's National Security Agency (NSA) did not ask Britain's GCHQ to spy on Donald Trump when he was running for president, the organisation's director, Admiral Mike Rogers, has insisted.
Probed on the allegations during questioning at US Congressional hearings, Admiral Rogers said such a move would "violate" US law and go against the "Five Eyes" intelligence sharing arrangements between America, Britain, Canada, Australia and New Zealand.
Asked if the NSA had requested GCHQ to monitor Mr Trump, Admiral Rogers said: "No sir, nor would I, that would be expressly against the construct of the Five Eyes agreement."
A diplomatic incident was sparked last week when the White House referenced a claim on Fox News that then President Obama could have used GCHQ for an operation against Mr Trump.
Admiral Rogers said he agreed with comments from the British Government that claims GCHQ was involved in surveillance on Mr Trump were "nonsense" and "utterly ridiculous".
Asked if President Trump making "baseless" claims against British security services damaged the close relationship between the two nations, the NSA director said: "I think it clearly frustrates a key ally of ours."
When pressed whether the incident would have a bad impact on security ties between the US and Britain, Admiral Rogers said: "I believe that the relationship is strong enough ... this is something we will be able to deal with."
Admiral Rogers moved to play down the impact of recent controversies on US relationships with the UK and Germany.
The NSA director said that close contacts between America and the two countries would not be set back "by anything in general", adding: "We have fundamental, foundational interests with each other, and we need to keep working together."
Mr Trump's press secretary Sean Spicer later appeared to call into question Britain's insistence that he had reassured officials that he would not repeat the allegations about GCHQ.
Asked at a regular press briefing if he told UK officials the White House would not repeat the claims, Mr Spicer replied: "There was merely an explanation of what we did and why we did it... and that was it."
FBI director James Comey also denied the suggestion made by Mr Trump in a tweet earlier this month that he had been bugged by Mr Obama.
At the hearings, Mr Comey said: "With respect to the president's tweets about alleged wiretapping directed at him by the prior administration, I have no information that supports those tweets, and we have looked carefully inside the FBI; the Department of Justice has asked me to share with you that the answer is the same for the Department of Justice in all its components.
"The department has no information that supports those tweets."