White House spokesman John Kirby to ABC: US has to be ready for Iran's response to Israeli attack that killed Nasrallah

White House National Security spokesman John Kirby said on ABC News that Hezbollah's command structure has been "nearly decimated" and that thousands of the group's drones and missiles have been destroyed.

"There's no question that the Hezbollah of today is not the Hezbollah that was even just a week ago," Kirby said.

Kirby also warned that the U.S. has to "be ready" for Iran to respond to the Israeli attack that killed Nasrallah and other leaders, saying that Iran's rhetoric "certainly suggests they're going to try to do something."

"We have to be prepared for some sort of response. We have to make sure that we are ready, and we are. We believe we have the force capability we need in the region, but it's not clear right now; it's too soon to know how Iran's going to react to this," he added.

Kirby's comments come as the U.S. ramped up its regional military posture. 

"We did deploy some additional forces into the region. I would tell you that there are other options available as well in terms of adding and enhancing that force posture," Kirby said.

Kirby's remarks come after Israel confirmed on Saturday that it had killed Hezbollah Secretary General Sayyed Hassan Nasrallah in a strike on Beirut on Friday.