WASHINGTON

Secretary of State Antony Blinken raised the possibility that the US response to an attack that killed three American soldiers in Jordan could be prolonged and multi-staged.

"We will respond, and that response could be multileveled, come in stages and be sustained over time," the top American diplomat told reporters Monday at the State Department during a joint press conference with NATO Secretary General Jens Stoltenberg.

"The president has been crystal clear. We will respond decisively to any aggression. And we will hold responsible the people who attacked our troops. We will do so at a time and a place of our choosing," he added.

A suicide drone attack on Sunday killed three American troops and injured at least 34 others at Tower 22, a remote military installation in Jordan near the Syrian and Iraqi borders. A group calling itself the Islamic Resistance in Iraq claimed responsibility.

The umbrella group is comprised of Iranian-backed militias that have been carrying out drone and missile attacks on US forces in the region for months amid Israel's ongoing war on the besieged Gaza Strip. Sunday's fatalities were the first to have resulted from the strikes.

US President Joe Biden has vowed to retaliate and is weighing a series of potential responses.

Amid the soaring regional tensions, Blinken said the region has not been as dangerous as it currently is for decades.

"I would argue that we've not seen a situation as dangerous as the one we're facing now across the region since at least 1973. And arguably, even before that, and that is the environment in which we're operating," he said.

Blinken was referring to the year that multiple Arab nations carried out a war on Israel in a conflict now known as the Yom Kippur War, or the Ramadan War.

National Security Council spokesperson John Kirby told reporters earlier Monday that Washington is "not looking for war" with Iran as it prepares its response to the fatal attack.

"We're not looking to escalate here. This attack over the weekend was escalatory. Make no mistake about it, and it requires a response. Make no mistake about that," Kirby said.

The Pentagon said Monday that the three service members were killed when the suicide drone hit their housing units. An investigation remains underway into the attack.

Kirby repeatedly declined to say whether the US is considering potential strikes inside Iran in response to Sunday's attack, maintaining he would not "telegraph punches," but reiterated that Washington is not seeking to go to war with Tehran.

"That said, this was a very serious attack. It had lethal consequences. We will respond, and we'll respond appropriately. I'm not going to telegraph what that's going to look like," he said.