Islamic State jihadists can now reportedly churn out passports using printing machines and blank passport books seized from the Syrian government — and may have already used one to sneak into the United States.

A 17-page Homeland Security Investigations Intelligence Report, issued to law enforcement last week, says ISIS likely has been able to print legitimate-looking Syrian passports since taking over Deir ez-Zour last summer, where a passport office with "boxes of blank passports" and a passport printing machine were located, ABC News first reported. 

Another passport office was located in Raqqa, the de facto capital of the Islamic State, ABC News reports.

"We have been aware of reports, not just in the press, that they may have obtained this capability," State Department spokesman John Kirby tells CNN. 

"Obviously, it's something that we take seriously. It's obviously something, clearly that we're mindful of."

The Homeland Security report includes a concern that it's possible someone "may have traveled to the U.S." using a fake passport, according to ABC News.

But Maine Independent Sen. Angus King says the United States is on the path to developing passports with chips that have biometric data that can't be faked.

"I think this tells us that we've got to accelerate doing that," he tells CNN. "But in the world of threats, of course, this is the one of them, but there are lots of other things we have to attend to as well."

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