An alleged weapons maker for the Islamic State (IS) claimed that a "radioactive device" has been smuggled into an undisclosed location in Europe, according to an intelligence brief released Monday by the SITE Intelligence Group.

"A Radioactive Device has entered somewhere in Europe," according Twitter user Muslim-Al-Britani, who claims to be a freelance jihadist weapons maker now working alongside IS (also known as ISIL or ISIS), according to tweets captured and disseminated by SITE.

BREAKING NEWS# WARNING A Radioactive Device has entered somewhere in Europe. pic.twitter.com/9GKHjz7ugs — Muslim-Al-Britani (@TNTmuslim) December 6, 2014

The claim by Al-Britani comes just days after reports emerged that IS could have in its possession a dirty bomb, the elements of which were obtained via earlier IS raids on a university research facility in Mosul that contained uranium. Al-Britani is also responsible for the flurry of reports on the dirty bomb.

Al-Britani, who has disseminated on his Twitter feed "weapon instructions and manuals," claimed on Nov. 23 that the "Islamic State does have a dirty bomb. We found some radioactive material from Mosul university," according to the tweets reproduced by SITE.

While it is difficult to assess the veracity of Al-Britani’s claims, U.S. officials have expressed concern about IS potentially smuggling nuclear and radioactive material out of Iraq.

U.S. and Iraqi officials inked a pact in September meant to step up efforts to combat this type of smuggling, which the United States deemed a "critical" threat.

"There’s always a concern about radiological or radioactive sources," a State Department official told the Washington Free Beacon at the time.

While the United States, at that time, was "not aware of any cases of these types of material being smuggled out of the country thus far," ISIL could potentially use these radioactive materials to create a crude bomb, the official said.

"This is the kind of thing where if ISIL got its hands on enough radioactive sources or radioactive sources of a sufficient radioactivity level and they decided to turn it into a bomb and blow it up in a market, that would be a very unpleasant thing," the official said.

Iraq reportedly informed the United Nations in July that terrorists had seized nuclear materials being housed at Mosul University. Some 90 pounds of uranium were said to have been stolen, according to reports.

Former Pentagon adviser Michael Rubin said that intelligence officials should be considering the information disseminated by purported IS confidants.

"Too often, counterterrorism officials plan to prevent replication of the last terror attack," Rubin said. "Terror groups, however, plan to shock with something new."

"Maybe Britani is lying, and maybe he’s not. But Western officials would be foolish to assume that just because something hasn’t happened yet, it won’t," Rubin said. "The terrorist groups have the motivation and, thanks to post-withdrawal vacuum created in Iraq, the means to strike the West like never before."

The threats also should factor into the ongoing debates about border control, according to Rubin.

"Perhaps it’s also time to recognize that open borders and successful counter-terrorism are mutually exclusive," he said. "It’s a lesson that might fly in the face of Obama’s ideology, but reality will always trump political spin."