UK Raises Terror Threat Level To 'Severe,' Cites ISIS

Although the British government says it has no evidence of an imminent attack, it has increased its terror threat level to "severe."

UK Raises Terror Threat Level To 'Severe,' Cites ISIS

New terrorism concerns Friday prompted the U.K. to raise its threat level from "substantial" to "severe."

PRIME MINISTER DAVID CAMERON VIA AL JAZEERA: "This is not some foreign conflict thousands of miles from home. … The ambition to create an extremist caliphate in the heart of Iraq and Syria is a threat to our own security here in the U.K."

That was British Prime Minister David Cameron referring to the threat of terrorist group ISIS, which controls portions of both Iraq and Syria. The U.K. cites the group as the reason for the increase in the threat level.

According to the British government, a threat level of "severe," its second highest of five, means an attack is "highly likely"; whereas, a threat level of "substantial" deemed the threat of terrorism a "strong possibility."

Despite that, U.K. officials have said there is no indication a terrorist attack is imminent.

In Cameron's statement, he also said as many as 500 U.K. citizens might have traveled to Iraq or Syria to participate in the conflict — and some of those returning home might pose a threat to the U.K. (Video via YouTube / Nahrwan Alsham)

According to USA Today, Cameron plans to consider new legislation to stop travel to ISIS-controlled areas — legislation he hopes will "tackle that ideology of Islamic extremism head on."

This all comes in the wake of the release of a grisly video that purportedly shows the execution of American journalist James Foley by a man with a British accent.

That has since kicked off a worldwide search for the alleged British extremist.

"Severe" is the highest the U.K.'s threat level has been since 2011. According to The Telegraph"At least one plot is known to have already been foiled," although the outlet provided no details on that alleged plot.

White House spokesman Josh Earnest said Friday the White House does not expect the terrorism threat level to increase in the U.S.