TRENTON -- Gov. Chris Christie told Fox News on Friday evening that there was no visible evidence that Donald Trump was ever placed under surveillance by U.S. intelligence services while president-elect.

"There certainly doesn't seem to be any evidence of that at this point," said Christie.

Earlier this week, FBI director James Comey had also testified that there was no evidence to support President Trump's tweeted claim that President Obama had him wiretapped at Trump Tower.

Appearing on Fox News' "Tucker Carlson Tonight," the governor was asked if given his background in federal law enforcement, he thought Trump's claims of President Obama ordering surveillance of Trump Tower were "plausible."

"I know from having spent seven years as a U.S. attorney that the FISA court, and the way that works, and foreign intelligence surveillance activities, it is very, very difficult to get that activity going," said the governor.

Christie, as a federal prosecutor, had tried terrorism cases -- like the Fort Dix Six -- that involved the Foreign Intelligence Surveillance Court, which was established and authorized under the Foreign Intelligence Surveillance Act of 1978 to oversee requests for surveillance warrants against foreign spies inside the United States.

"You have to go and convince an independent judge. And, as a prosecutor, it was our job to provide that information along with the Department of Justice, to do it. ... I can tell you from my experience, that kind of stuff was difficult to get," he said.

However, U.S. Rep. Devin Nunes (R-Calif.), the House Intelligence Committee chairman, claimed this week that he had "seen intelligence reports that clearly show that the president-elect and his team were, I guess, at least monitored," albeit it "lawfully" and in "incidental" surveillance related to an investigation of members of Trump's campaign to see if they had colluded with Russian intelligence to influence the election.

Nunes told the Daily Beast on Friday that he was "the only one" who'd seen classified documents showing Trump associates were the subject of "legally collected foreign intelligence under FISA," the Foreign Intelligence Surveillance Act.

Claude Brodesser-Akner may be reached at cbrodesser@njadvancemedia.com. Follow him on Twitter @ClaudeBrodesser. Find NJ.com Politics on Facebook.