Europe and U.S. face bigger terror attacks as ISIS loses ground in Mideast, FBI and CIA chiefs both warn

Mourners gather after 84 people were killed in a terrorist attack on July 14, 2016 when a 19-tonne cargo truck was deliberately driven into crowds celebrating Bastille Day on the Promenade des Anglais in Nice, France.Reuters

The heads of both the FBI and the CIA are saying the same thing: Europe and America should brace for bigger terrorist attacks as the Islamic State (ISIS) continues to lose ground in Syria and Iraq.

On Wednesday, FBI Director James Comey warned that hundreds of terrorists could fan out to infiltrate western Europe and the U.S. to carry out attacks on a wider scale, Bloomberg reports.

"At some point there's going to be a terrorist diaspora out of Syria like we've never seen before," Comey said at a conference on cybersecurity in New York City, adding that "the future of this threat" was recently seen in Brussels and Paris.

He warned that future terrorist attacks could be on "an order of magnitude greater."

CIA Director John Brennan issued basically the same warning when he spoke before the U.S. Senate Intelligence Committee last month. He said "our efforts have not reduced the [ISIS] terrorism capability and global reach."

"As the pressure mounts on [ISIS], we judge that it will intensify its global terror campaign to maintain its dominance of the global terrorism agenda," Brennan warned.

Terrorist attacks in France alone have killed more than 230 people since the start of last year, according to Bloomberg. Last month, 49 people were killed during a mass shooting at a nightclub in Orlando, Florida, carried out by a man who claimed allegiance to ISIS.

Comey said the violence directed or inspired by the ISIS poses as "the greatest threat to the physical safety of Americans today."

Worse, he admitted that counterterrorism officials are finding it difficult to prevent "lone-wolf" attackers acting on ISIS' calls for violence.

According to Bloomberg, the FBI chief's comments reflect a consensus among U.S. intelligence officials that ISIS will inevitably strike out abroad as it continues to lose ground militarily in Syria and Iraq under attack from a U.S.-led coalition.

U.S. officials have claimed increasing success in regaining territories captured by ISIS in Syria and Iraq.

"We can say that the tide has turned," Secretary of State John Kerry said last week. "Our coalition and partners on the ground have driven Daesh [Arabic name for ISIS] out of nearly 50 percent of the territory that it once controlled in Iraq and 20 percent of the territory in Syria," he added.

Without providing details, Republican presidential nominee Donald Trump has said he would be more aggressive in attacking ISIS if elected in November. Concerning the threat of attacks in the U.S., Trump has vowed to introduce "extreme vetting" of potential immigrants from certain "territories" affected by terrorism.