Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff (AP Photo/Jacquelyn Martin)

(CNSNews.com) - Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, said at a Pentagon press briefing yesterday that “because of open borders and immigration issues,” the Islamic State of Iraq and the Levant (ISIL) is an “immediate threat.”

In the context of this ISIL threat, Dempsey said he had had conversations with his European colleagues "about their southern flank." He did not specifically mention the U.S.-Mexico border, which is the southern flank of the United States.

Seven years ago, then-National Intelligence Director Mike McConnell publicly warned that terrorists were coming across the U.S.-Mexico border, and that "a significant number of Iraqis" had been "smuggled across illegally" the previous year.

"Now some we caught, some we didn't," McConnell told the El Paso Times in an interview published on Aug. 22, 2007. "The ones that get in, what are we going to do? They're going to write home. So, it's not rocket science, word will move around.

At yesterday's Defense Department briefing, a reporter asked Dempsey and Secretary of Defense Chuck Hagel: “Is it the calculation, though, that ISIL presents a 9/11 level threat to the United States?”

“ISIL is as sophisticated and well-funded as any group that we have seen,” said Hagel. “They're beyond just a terrorist group. They marry ideology, a sophistication of strategic and tactical military prowess. They are tremendously well-funded.

“Oh, this is beyond anything that we've seen,” said Hagel. “So we must prepare for everything. And the only way you do that is that you take a cold, steely, hard look at it and get ready.”

Dempsey then added that the immediacy of the threat arose from non-Middle Easterners who had travelled to the area controlled by ISIL and who shared the group’s “ideology.”

“Well, the immediacy is in the number of Europeans and other nationalities who have come to the region to become part of that ideology,” said Dempsey. “And those folks can go home at some point. It's why I have conversations with my European colleagues about their southern flank of NATO, which I think is actually more threatened in the near term than we are.

“Nevertheless,” Dempsey continued, “because of open borders and immigration issues, it's an immediate threat. That is to say, the fighters who may leave the current fight and migrate home.

“Longer term, it's about ISIL's vision,” said Dempsey, “which includes -- I actually call ISIL, here we go, right, ISIS, I-S-I-S, because it's easier for me to remember that their long-term vision is the Islamic State of Iraq and al-Sham. And al-Sham includes Lebanon, the current state of Israel, Jordan, Iraq, Syria and Kuwait.

“If they were to achieve that vision, it would fundamentally alter the face of the Middle East and create a security environment that would certainly threaten us in many ways,” said Dempsey.

In the past, federal officials have publicly stated that terrorists have come across the U.S.-Mexico border into the United States.

A man wades across the Rio Grande River in the U.S.-Mexico border. (AP Photo/Christopher Sherman)

Then-Director of National Intelligence Mike McConnell told the El Paso Times in 2007: “So are terrorists coming across the Southwest border? Not in great numbers.”

When a reporter followed-up, asking McConnell if there were “some cases,” McConnell said: “There are some. And would they use it as a path, given it was available to them? In time they will.”

A reporter asked: "If they're successful at it, then they'll probably repeat it."

"Sure," said McConnell. "There were a significant number of Iraqis who came across last year. Smuggled across illegally."

"Where was that?" a reporter asked.

"Across the Southwest border," said McConnell.

"Can you give me anymore detail?" a reporter asked.

"I probably could if I had my notebook," said McConnell. "It's significant numbers. I'll have somebody get it for you. I don't remember what it is. The point is it went from a number to (triple) in a single year, because they figured it out. Now some we caught, some we didn't. The ones that get in, what are they going to do? They're going to write home. So, it's not rocket science, word will move around. There's a program now in South America, where you can, once you're in South American countries, you can move around in South America and Central America without a visa. So you get a forged passport in Lebanon or where ever that gets you to South America. Now, no visa, you can move around, and with you're forged passport, as a citizen of whatever, you could come across that border. So, what I'm highlighting is that something."

"Is this how it happened, the cases you're talking about?"

"Yes," said the then-Director of National Intelligence.

In August 2009, the Government Accountability Office reported that in fiscal 2008 “there were three individuals encountered by the Border Patrol at southwest border checkpoints who were identified as persons linked to terrorism.”

“In addition,” said that 2009 GAO report, “the Border Patrol reported that in fiscal year 2008 checkpoints encountered 530 aliens from special interest countries, which are countries the Department of State has determined to represent a potential terrorist threat to the United States. While people from these countries may not have any ties to illegal or terrorist activities, Border Patrol agents detain aliens from special interest countries if they are in the United States illegally and Border Patrol agents report these encounters to the local Sector Intelligence Agent, the Federal Bureau of Investigation (FBI) Joint Terrorism Task Force, U.S. Immigration and Customs Enforcement (ICE) Office of Investigations and the CBP National Targeting Center.”