Washington: US Central Intelligence Agency Director John Brennan warned that the Islamic State (IS) terror group wants to conduct Istanbul airport-style attack in America. "I am worried from the standpoint of an intelligence professional who looks at the capabilities of IS... and their determination to kill as many as people as possible and to carry out attacks abroad," Brennan said on Wednesday in an interview with Yahoo News. "I'd be surprised if IS is not trying to carry out that kind of attack in the US," said Brennan. At least 42 people were killed and over 200 others injured in a deadly terror attack that hit Ataturk Airport on Tuesday night. Turkish media reported that the country's intelligence units sent a warning letter to related state institutions about potential attacks by the IS nearly 20 days ago. Hande Firat, CNNTurk's representative in Ankara, said on a live broadcast that Ataturk Airport was listed as a potential target in the letter. As of now, no group has claimed responsibility for the attacks. While he did not confirm that IS was behind the attack on Tuesday, Brennan said that choosing suicide bombing as the method of attack "is usually more of an IS technique".