There is “no doubt” ISIS is recruiting youth in North Texas, by targeting them over the internet, said Special Agent in Charge of the Dallas FBI, Tom Class. He added that Islamic State terrorists in Iraq and Syria alter their tactics to make it harder for federal agents to track them online.

Class, who took over the helm of the Dallas FBI this Spring, told KXAS 5 (NBC) he sees ISIS recruiting aggressively, using social media to reach young people in North Texas. He said that often starts out in the open on popular sites including Facebook and Twitter, but then ISIS recruiters move the conversations to encrypted websites or “go dark” on the internet to places called the “dark web” where technology and U.S. privacy laws limit what agents can do. It makes it harder for the FBI to track.

“It’s the most significant threat to the country, the most significant threat to our national security and it’s the FBI’s top priority,” said Class in comments made to the Dallas NBC affiliate weeks before the ISIS terrorist attack in Paris that left at least 129 dead on November 13. “We have active investigations, counter-terrorism investigations every day.”

Class previously served as Section Chief of the High Value Detainee Interrogation Group in the national Security Branch at FBI Headquarters, which interrogates high level terror suspects. He worries about staying ahead of the “dark web” threat. In September, he told the Dallas Morning News, the terrorists reach out to “disenchanted” young people in North Texas to launch terror attacks, adding that fighting these “homegrown violent terrorists” is one of his biggest challenges that keeps him “up at night.”

FBI Director James Comey told WJZ 13 (CBS) Baltimore in June that more and more Americans are engaging online with ISIS. He underscored they have no way of stopping it. The Islamic State’s sophisticated online recruiting methods are nearly impossible to find because once users message privately with these terrorists, they exchange codes and talk on encrypted networks that prevent agents from intercepting their cyber chat. Comey noted that “people they are tasking, trying to enlist to kill people, they move them to an encrypted–end to end encrypted–mobile messaging app so we can’t see them.”

Federal agents scour social media in search of communications among Dallas-area residents and Islamic State-linked accounts. Nationwide, for agents trying to uncover those messages it is like trying to find a needle in a haystack. That haystack “keeps getting bigger and bigger,” said Dallas Assistant Special Agent Ryan Young, who spoke to the Dallas Morning News in September. He cautioned that dozens of ISIS Twitter accounts are run by web-savvy British fighters in Syria who tweet to 18,000-plus English-speaking followers, many of them are in the United States.

Class called these methods very successful for the extremists in the KXAS 5 interview. “We’re always going to be a little bit behind,” he said, acknowledging the difficulty of keeping up with such fast-changing technology, although U.S. privacy laws impede agents’ abilities to uncover important information online about ISIS activities.

The Dallas FBI chief touched on the local Garland attack last May when ISIS claimed credit after two gunmen opened fire outside the Muhammad Art Exhibit and Contest organized by Pamela Geller. Garland police swiftly took down the two shooters, killing both. Class called the thwarted massacre significant because it was ISIS-inspired and showed how quickly “chatter can turn into action.” He said that the FBI saw one of the two shooters talk online about Garland before the event and alerted police to the chatter but they did not realize the two extremists would drive from Phoenix to Garland to attempt an attack.

It is a terrifying reality for which the FBI does not yet have an answer. “I do not have an easy solution, but I want to make sure the American people know about this and that we as a democracy talk about it,” said Comey in the Baltimore TV news coverage.

On Thursday, GOP Presidential front runner Donald Trump pointed out the threat ISIS poses in how they use the internet “far better than we do.” Breitbart News reported that Trump said we have to not only be a force on the internet but take it over to beat ISIS. He told Breitbart Executive Chairman Stephen K. Bannon on Sirius XM’s Breitbart News Daily Radio program,”at some point they’re not going to go over to fight for ISIS over there, they’re going to stay right here and fight for ISIS.”

Class told KXAS 5 it is more important than ever for the FBI to reach out to North Texas communities, including local mosques and be part of a community conversation that discourages minors from engaging with ISIS online. The bureau hopes to build relationships so people will reach out to them if they see disconcerting changes in a youth’s behavior that could be ISIS recruitment related.  He asked for the public’s help when they see something suspicious-looking, adding no tip is too small.

The Dallas FBI Chief said that other cities face similar threats. “The threat’s not going to go away. It will morph into different areas I’m sure, but we’re in for the battle of a lifetime really.”

Follow Merrill Hope on Twitter @OutOfTheBoxMom.