The United States’ top intelligence official says the U.S. government has not yet verified that the Islamic State group is responsible for the Manchester attack.

Dan Coats, the director of national intelligence, told Congress that the extremist group frequently claims responsibility for terror attacks.

The Islamic State group says one of its members planted bomb in crowds in the suicide attack at an Ariana Grande show Monday night that left 22 people dead. The group warned in a statement on social media that more attacks are to come.

Testifying Tuesday before the Senate Armed Services Committee, Coats says though he was aware of the IS claim of responsibility, U.S. authorities hadn’t yet verified that.

He says the Manchester attack is a reminder the terrorist threat is real. He says, “It’s not going away and it needs significant attention.”