Three US Army soldiers were killed and several others injured after an unmanned aerial drone struck the troops near the Syrian border in northeastern Jordan on Sunday.
At least 34 personnel were injured in the attack and is expected to rise, according to a statement from US Central Command. Eight personnel were evacuated from Jordan for higher medical assistance.
US President Joe Biden has blamed Iran-backed groups for the attack, the first deadly strike against US forces since the Israel-Hamas war began in October.
"While we are still gathering the facts of this attack, we know it was carried out by radical Iran-backed militant groups operating in Syria and Iraq. Have no doubt - we will hold all those responsible to account at a time and in a manner of our choosing," Biden said in a statement.
However, Iran's mission to the United Nations said in a statement on Monday that Tehran was not involved in the attack.
The Islamic Resistance in Iraq, an umbrella organisation of Iran-backed militant groups, claimed the attack on the Jordan-Syria border.
Location
The drone hit the military outpost in Tower 22, a strategically important location in Jordan, at the most northeastern point where the country's borders meet Syria and Iraq.
Purpose of hitting Tower 22
Little publicly known, the base stations 350 US Army and Air Force troops and includes logistics support. Tower 22 is located near the Al Tanf garrison across the border in Syria and houses small US troops. Tanf had been key in the fight against Islamic State and has assumed a role as part of a US strategy to contain Iran's military build-up in eastern Syria.
US troops in Jordan
{{/usCountry}}Little publicly known, the base stations 350 US Army and Air Force troops and includes logistics support. Tower 22 is located near the Al Tanf garrison across the border in Syria and houses small US troops. Tanf had been key in the fight against Islamic State and has assumed a role as part of a US strategy to contain Iran's military build-up in eastern Syria.
US troops in Jordan
{{/usCountry}}Since the start of the Syrian conflict in 2011, the US has spent millions of dollars to help Amman set up an elaborate surveillance system to stem infiltration by militants from Syria and Iraq.
Jordan's army is one of the largest armies which receives financial and military aid from Washington. It is one of the few regional allies that hold extensive exercises with the US Army throughout the year.
The attack is a major escalation of the already tense situation in the Middle East, where war broke out in Gaza after Palestinian Islamist group Hamas' attack on Israel which killed 1,200. Israel's subsequent assault on Gaza has killed over 26,000 Palestinians, according to the local health ministry.
(With inputs from Reuters)