Istanbul attack bears `hallmark` of IS: CIA director

District of Columbia: The suicide assault on Istanbul`s Ataturk airport bears the "hallmark" of an Islamic State attack, CIA Director John Brennan said Wednesday.

No group has claimed responsibility for Tuesday`s attack, which killed 41 people and wounded 239 more.

"The despicable attacks in Istanbul International Airport yesterday that killed dozens and injured many more certainly bears the hallmark of ISIL`s depravity," Brennan said, using an acronym for the IS group.

Witnesses described scenes of terror and panic as the attackers began shooting indiscriminately and then blew themselves up at the entrance to Ataturk airport, one of Europe`s busiest hubs.

The attack followed coordinated IS suicide bombings in March at the Brussels airport and a city metro station that left 32 people dead.

Brennan said the IS group typically does not claim responsibility for attacks in Turkey, so it can send a message to the Turkish government without alienating potential future recruits in the country.

America`s top spy added that the IS group may well be planning a similar attack in the United States.

"If anyone believes that the US homeland is hermetically sealed... I would guard against that," he said.

Earlier this month, a gunman killed 49 people at a Florida gay nightclub in the deadliest terror attack on US soil since September 11, 2001.

The shooter, US-born Omar Mateen, pledged allegiance to the IS group while carrying out the attack.