The United States has shown it won’t “shy away” from responding to attacks against its personnel when necessary, the Pentagon said on Wednesday, after a rocket attack against Iraq’s Ain al-Asad air base, which hosts U.S., coalition and Iraqi forces.

“Let’s do this the right way. Let’s let our Iraqi partners investigate this, see what they learned,” Pentagon spokesman John Kirby told a news briefing, calling the attack a “troubling development.”

“And then, if a response is warranted, I think we have shown clearly that we won’t shy away from that. But we’re just not there yet,” Kirby addded, firmly declining to speculate about whether a response was likely.

There were no reports of injuries among U.S. service personnel but an American civilian contractor died after suffering a “cardiac episode” while sheltering from the rockets, the Pentagon said.

(Reporting by Phil Stewart and Idrees Ali, Editing by Franklin Paul)