The US Homeland Security Investigations (HSI) in an intelligence report issued to law enforcement last week stated that the Islamic State (Daesh) terrorists may have their own passport-printing machines.
The report has asked the authorities to stay alert as Isis may have sent jihadis with Syrian passports printed in Daesh territories, according to ABC News.
The 17-page report states that Isis terrorists may have taken over Syrian passport offices in Deir ez-Zour and Raqqa.
"Since more than 17 months [have] passed since Raqqa and Deir ez-Zour fell to Isis, it is possible that individuals from Syria with passports 'issued' in these Isis controlled cities or who had passport blanks, may have travelled to the US," the report says.
The Homeland Security has further warned if the production of passports in Isis territories is not controlled, "their operations will continue to increase and expand outside of their operational controlled areas."
FBI Director James Comey on 9 December, while testifying before lawmakers, confessed that the agency was concerned about Isis' capability of printing its own passports.
"The intelligence community is concerned that they [ISIS] have the ability, the capability to manufacture fraudulent passports, which is a concern in any setting," Comey said.
The report has come just weeks after it was found that at least one of the Isis Paris attackers might have come to France on a boat along with the refugees using fake Syrian passport.