Boy arrested in alleged ISIS-inspired plot to attack Pope Francis during his US visit

Pope Francis waves to the faithful during his Sunday Angelus prayer in Saint Peter's square at the Vatican, on Sept. 13, 2015.Reuters

The Federal Bureau of Investigation (FBI) arrested a 15-year-old boy outside Philadelphia last month for alleged threats to launch an Islamic State-inspired attack against Pope Francis when he visits the United States next week, ABC News learned on Tuesday, a week before the pontiff's Sept. 22 Washington arrival.

"The minor was inspired by [ISIS] and sought to conduct a detailed homeland attack which included multiple attackers, firearms, and multiple explosives, targeting a foreign dignitary at a high-profile event," according to a joint intelligence bulletin issued by the FBI and Department of Homeland Security that was issued to law enforcement agencies in the US last Aug. 14, ABC News said.

In the bulletin, a "foreign dignitary" was mentioned referring to the Pope, who will culminate his US trip with a visit to Philadelphia.

House Homeland Security Committee Chairman Mike McCaul on Sunday revealed that US authorities "have disrupted one particular case" about a plan to attack Pope Francis.

"The minor obtained explosives instructions and further disseminated these instructions through social media," read the joint intelligence bulletin.

The suspect was charged with attempting to provide material support to a terrorist organisation and attempting to provide material support to terrorist activity, ABC News said.

Quoting sources, ABC News said any threat from the suspect was not imminent and his plans were "aspirational," adding that there were questions about the boy's mental health.

Law enforcement officials said there is no specific threat to the Pope during his visit to the US next week.

"The FBI is working closely with the United States Secret Service and our federal, state and local partners in advance of the papal visit to ensure the safety and security of all," a spokeswoman for the FBI Philadelphia said.

The FBI-DHS bulletin noted that "several recent instances demonstrate some youth are vulnerable to messaging from [ISIS] and its supporters."

ISIS has been known to use social media to encourage supporters to launch attacks.

Their "innovative use of social media and messaging has played a key role in motivating young US-based males and females to travel to join the self-declared Islamic State or allegedly attempt to conduct attacks in the Homeland on behalf of" ISIS, according to the bulletin.

"These incidents also show that some US-based youth are willing to connect over social media with like-minded persons, and have proven adept at obfuscating such social media usage from their parents and guardians," the bulletin said.