
Iran has denied involvement in a drone attack on a US base near Jordan's border with Syria that killed three US troops.
The US blamed the attack on "radical Iranian-backed militant groups" which also left dozens injured.
US President Biden vowed revenge and said: "We shall respond."
It is the first time that a strike has killed US troops in the region since Hamas's 7 October attack on Israel.
There have been other attacks on US bases in the region, but before Sunday there were no fatalities, according to the US military.
The Islamic Resistance in Iraq claimed it was behind that attack.
The umbrella group emerged in late 2023 and is comprised of several Iran-affiliated militias operating in Iraq. It has claimed other attacks against US forces in recent weeks.