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Sean Spicer
Members of Trump's inner circle have sparred with lawmakers and intelligence officials over the matter for nearly two weeks.
During a White House press briefing on Thursday, Spicer cited comments from Fox News commentator Andrew Napolitano that Spicer said confirmed Britain's Government Communications Headquarters (GCHQ), an intelligence agency, took part in a spy operation at Trump Tower during the 2016 US election.
"Three intelligence sources have informed Fox News that President Obama went outside the chain of command," Spicer said, reading from notes in the White House press room on Thursday. "[Obama] didn't use the NSA, he didn't use the CIA, he didn't use the FBI, and he didn't use the Department of Justice. He used GCHQ, what is that? It's the initials for the British Intelligence Spying Agency," Spicer said.
A spokesperson for the GCHQ quickly issued a statement debunking the Fox News report Spicer was referencing.
"Recent allegations made by media commentator judge Andrew Napolitano about GCHQ being asked to conduct 'wiretapping' against the then president-elect are nonsense," the statement read. "They are utterly ridiculous and should be ignored."
Spicer engaged in a heated discussion with reporters on Thursday about Trump's wiretap claims - which Trump had appeared to walk back during an interview on Fox News the night before.
Trump has previously urged congressional lawmakers to look into the matter. The Senate Intelligence Committee has, and issued a joint statement on Thursday saying it sees "no indications" Trump was wiretapped.