FBI agent and Twin Towers first responder reveal how likely another 9/11 attack is on U.S. soil...and why it will be even more deadly

A terrorist attack on U.S. soil is a near certainty and will be even more deadly than the 9/11 tragedy, two counter-terrorism experts told DailyMail.com.

That's largely due to the massive influx of illegal and unvetted foreign nationals into the country through the U.S.-Mexico border. 

A former high-ranking FBI official and a 25-year combat veteran specializing in terrorism and hostage rescue say the threat of an explosive or gun-operated attack is not a matter of if but when.

And the attack is likely to be bicoastal as terrorist cells have set up shop all over the country. 

Bryan Stern, the veteran who founded Grey Bull Rescue Foundation, and Chris Swecker, former FBI Assistant Director of the Criminal Investigation Division, say the threat of '9/11 2.0' is even higher after multiple ISIS-affiliated operatives were arrested in the U.S. interior this week.

The two terrorism experts warned DailyMail.com that a future attack on U.S. soil will certainly be far worse than the Boston Bombing (shown above) or the 9/11 tragedy. Both referenced how cells of terrorists are already operating within the U.S. and a recent report highlighting the arrest of eight ISIS-affiliated terrorists indicates the 'sloppy' work of multiple federal agencies

Eight Tajikistan nationals crossed through the porous U.S. southern border, were screened, passed security checks and were released into the country before having to be arrested by Immigration and Customs Enforcement (ICE) officials after the FBI tipped the officers off to the migrant's ties to ISIS.

And earlier this week lawmakers confirmed to DailyMail.com exclusively that there are confirmed terror cells operating in the U.S. and Biden's border policies make it 'easy' for bad actors to enter the heartland. 

Now, the security experts are sounding the alarm on how serious this failure is and how it reveals the easy it is for 'bad guys' to infiltrate America. 

'A bunch of bad guys, who are known bad guys, were caught by law enforcement on the border - that's bad,' Stern, who was a first responder during the twin tower attacks said. 

'Then they were run through checks, came back clean and were then let go - and then had to go get re-caught again, loose on the streets of America. That demonstrates that, at least in this case, the lessons of 9/11 weren't learned.'

'You would think we would have a really good understanding of how to intercept bad guys and what to do with them once they're caught, so that they're not allowed entry into the United States.'

He noted the trillions of taxpayer dollars that have been funneled to counter-terrorism efforts, including the growth of the intelligence community (IC) and the birth of the Department of Homeland Security (DHS) following 9/11. 

The attacks the two experts expect are not as 'spectacular' as those of 9/11, but likely would occur in crowded areas across multiple cities simultaneously utilizing bombs and guns

Their sounding the alarm on a possible attack comes the same week that eight ISIS-affiliated migrants from Tajikistan passed through the U.S.-Mexico border undetected before later being arrested 

Swecker and Stern both indicated that there are likely many more terrorists, some who may have ties to ISIS, who are operating currently within the U.S.

Though, he said, the vector of the attack would be much different from those of September 2001. 

'I think the next 9/11 will be very low tech, very high impact and very dispersed. I don't think it'll be focused in one spot.'

'So you know, 10 different events at the same time, using low technology that's hard to attribute to anyone or anything,' Stern continued.

'Right now we look at 9/11 as the seminal terrorist event in American history. With 9/11 2.0, I submit to you, we will look back on 9/11 and say, 'wow, that wasn't that bad.' That's how big it will be.'

He speculated that small groups of gunmen or bomb makers would be the most effective way for anti-American actors to cause devastation upon the U.S. 

Swecker, in a separate interview, said much of the same.

'I don't fear the 9/11 style of attack,' he told DailyMail.com. 'I think that's sort of how that's old fashioned, if you will.'

The attack, he said, would likely come from 'small cells,' would be 'low-tech' and  could occur in 'cities, through subways, transportation centers [and] marching events' that have 'a lot of attendees.'

'If they get in the country with a three or four band cell shooting and or with explosives, in a subway, in a complex environment, it'll destroy the psyche of this country in terms of striking fear, which is what terrorists want to do,' Swecker said. 

He noted the ISIS-inspired attack by Tajik nationals on the Moscow music hall earlier this year as an indication of what could happen here. 

Swecker also noted how FBI Director Christopher Wray has recently said as much under oath to Congress. 

Stern helped evacuate people from Afghanistan after the U.S. military withdrawal and previously served for 25 years in the U.S. military focusing on terrorism 

Former FBI assistant director Chris Swecker told DailyMail.com the agency needs to refocus on America's most pressing threats, terrorism and the U.S.-Mexico border

'Increasingly concerning is the potential for a coordinated attack here in the homeland, not unlike an attack we saw in the Russia theater,' Wray told lawmakers June 4. 'We have seen the threat from foreign terrorists rise to a whole other level.'

Wray also expressed major concern over the U.S.-Mexico border's role in terrorist plots within the heartland. 

'Individuals who when they come in are armed with fake documents or snuck in some way or individuals of whom there's not enough derogatory information in the intelligence community to watchlist them,' have been of particular concern, Wray testified.

'As we have less collection overseas against foreign terrorism, there's less sources of information' to denote which individuals entering the U.S. are threats, the FBI director said. 

Further, that same day in early June, Attorney General Merrick Garland also noted how the threat of attacks on Americans has exploded.  

'I am worried about the possibility of a terrorist attack in the country after October 7,' Garland said. 'The threat level for us has gone up enormously.'

'Every morning, we worry about this question. We try to track anyone who might be trying to hurt the country,' he continued. 'Of course, this is a major priority for the Justice Department.'

So as the U.S.'s top law enforcement officials are sounding the alarm so are the security experts. 

In fact, Swecker was so concerned over the threats emanating from the border that he published a letter alongside other FBI and DHS officials in January decrying the steady stream of military-aged migrants illegally crossing into America. 

He and his co-signers said in the letter an attack on Americans is 'imminent.' 

Migrants are processed by the U.S. Border Patrol near the Jacumba Hot Springs after crossing the US-Mexico border on June 13, 2024 in San Diego, California.

Swecker warned in a January letter that many of the migrants entering are military aged

This week he told DailyMail.com: 'Frankly, we should have thousands of FBI agents on the border right now helping vet these people and running operations on these people coming across the border.' 

The former FBI assistant director added it would have great benefits for the agency's efforts, saying the intelligence gathered would be a 'bonanza.' 

Additionally, he said the arrest of the eight ISIS-affiliated Tajiks 'is not impressive.' 

He noted that is just one instance that got reported and many more similar situations where terrorist-friendly migrants cross likely go underreported or worse, undetected by authorities. 

Stern echoed Swecker's concern over the IC's and DHS's 'sloppy' inability to stop suspected terrorists. 

'They're known ISIS, bad guys from Tajikistan, which borders Afghanistan. And they were let loose on the streets of America for some period of time, until someone said, 'oops, that's bad, let's go find these guys.''

DHS Sec. Alejandro Mayorkas testified before Congress this year the border is in 'crisis'

Swecker suggested that the FBI surge agents to the U.S.-Mexico border to assist with intelligence gathering and migrant vetting

'It sounds like that they were a little sloppy,' Stern told DailyMail.com. 

The former FBI official said that sloppiness is likely a result of the DOJ's gung-ho effort to tackle radical white supremacy, which President Joe Biden said in 2023 was the 'most dangerous terrorist threat' facing America. 

Biden saying 'White supremacy extremists, or something like that, are the greatest threat to this country,' Swecker mentioned, adding 'nothing could be further from the truth.'

'So we're diverting resources to places that are not the greatest threat,' he continued. 

His former colleagues that are still at the FBI, or have recently retired from the agency, told him they are being thwarted by leadership from being 'proactive' in combatting terrorist threats. 

'The primary mission is, is sort of taking a back seat to other political initiatives such as DEI and such. I hate to say, I don't want to make this political, but the Justice Department has clearly politicized the agencies.'

And of the estimated 10 million migrants who have crossed into the country under Biden, including 300 with ties to terrorism, Swecker said, you cannot cannot believe that there aren't terror cells here.'

Stern was also incredulous at the state of the U.S.-Mexico border. 

'If you're if you're a Tajik and you're caught at the border coming in illegally, we should already be suspicious of you because you're already breaking the law.'

'We're a hospitable country and we have policies and laws that allow for this humanitarian parole, asylum, all those things. But If you're caught sneaking across the border of violating U.S. law, well, then you should start off as you're a criminal.'

The veteran counter terror expert concluded with a chilling warning. 

'We'll look back at 9/11 and we're gonna say 'wow, only almost 3,000 people were killed. That's not that bad.''