Updated

A teenager’s ISIS-inspired plot to attack Pope Francis during his U.S. visit was more "aspirational" than operational, a law enforcement source confirmed to Fox News on Tuesday.

The 15-year-old was arrested in the Philadelphia area in August, when law enforcement authorities foiled the plot.

The plot is the same one Rep. Mike McCaul, R-Texas, the Homeland Security chairman, referred to during an interview on Sunday, a source told Fox News.

“We are monitoring very closely threats against the pope as he comes into the United States,” McCaul said on ABC’s “This Week.” “We have disrupted one particular case.”

Pope Francis was not named as the specific target of the plot in an Aug. 14 FBI and Department of Homeland Security joint intelligence bulletin that said the teen planned to use multiple attackers, firearms and explosives to target a “foreign dignitary at a high-profile event.” The bulletin said the minor was radicalized via social media.

The teen may suffer from mental health issues, a law enforcement source told Fox News, though the source wouldn't detail specifics about the teen's condition.

McCaul on Sunday also acknowledged the potential for a so-called “lone wolf” attack nationwide and said he was briefed by the Secret Service “in a classified setting” about the pope’s visit.

“I’m concerned,” McCaul said. “He is a very passionate man. He likes to get out with the people. And with that comes a large security risk…But as that date approaches, I think we’re all very vigilant to protect him as he comes into the United States.”

Fox News’ Matt Dean contributed to this report.