CIA Director John Brennan said that the suicide bombings in Istanbul, Turkey bore the signs of ISIS and should serve as a warning to Americans that the terrorist group is aiming to carry out similar attacks in the U.S.
"I’d be surprised if [ISIS] is not trying to carry out that kind of attack in the United States," Brennan told Yahoo News Tuesday evening.
Although no organization has claimed responsibility for the bombings at Istanbul Ataturk Airport Tuesday night, Brennan said the method of attack fits the profile of the terror group.
Three suicide attackers wearing explosive vests opened fire and blew themselves up in the airport’s arrival hall and a nearby parking lot, killing 41 people and wounding 239. The coordinated massacre echoed the ISIS bombings at Brussels Airport three months earlier.
Turkish Prime Minister Binali Yildirim told reporters hours after the Istanbul bombings that initial findings implicated ISIS. While the Kurdistan Workers' Party, or PKK, has targeted police and military personnel with bombs during the past year, officials said ISIS is more likely behind Tuesday's attack.
"I am worried from the standpoint of an intelligence professional who looks at the capabilities of [ISIS] … and their determination to kill as many as people as possible and to carry out attacks abroad," Brennan said.
He said ISIS has so far been unable to attack the U.S. directly because of effective homeland security and intelligence measures, but warned that the militants would continue their attempts to infiltrate American defenses.
Director of National Intelligence James Clapper raised similar concerns last month. He told CNN in May that ISIS has the capability to conduct a large-scale Paris-style attack in the U.S.