The US military says three have been killed and at least 34 others wounded in the attack on US forces in northeastern Jordan.
Three US soldiers were killed and at least 34 others were wounded in a drone strike in northeastern Jordan near the border with Syria, the United States military said.
“While we are still piecing together the facts of this attack, we know it was carried out by Iranian-backed radical militant groups operating in Syria and Iraq,” President Joe Biden said in a statement on Sunday.
He said the U.S. “will hold all those responsible to account every time and in every way [of] our choice”.
The Islamic Resistance in Iraq, an umbrella group of Iranian-backed armed groups, claimed attacks targeting three bases, including one on the Jordanian-Syrian border.
Jordan on Sunday condemned a “terrorist attack” on a military outpost just inside its border with Syria and said it was working with Washington to secure its border.
In the first official statement on the attack, US ally Jordan said it was working with Washington to “fight terrorism”. Earlier, Jordanian state television quoted Muhannad Mubaidin, a Jordanian government spokesman, as saying the attack took place outside the kingdom across the border in Syria.
The deaths are the first for US troops in the Middle East since Israel's war on Gaza began on October 7.
The attack comes amid heightened tensions in the region, where Israel continues its war on Gaza in response to an attack by the Palestinian group Hamas in southern Israel that killed at least 1,139 people, according to Israeli authorities.
Israel's subsequent assault on Gaza killed more than 26,400 people, according to Palestinian officials in the besieged territory.
“Regional War”
Fears have grown of a regional conflagration amid attacks by Yemen's Houthi rebels on ships in the Red Sea and near-daily rounds of cross-border fire between Israel and the Lebanese armed group Hezbollah.
In recent weeks, armed groups backed by Iran have stepped up attacks on US military bases in Iraq and neighboring Syria in response to Israel's military campaign in the Gaza Strip.
Iran-backed groups have characterized their strikes as retaliation for Washington's support for Israel's war in Gaza and say they aim to push US forces out of the region.
The US in recent months has struck targets in Iraq, Syria and Yemen to respond to attacks against US forces in the region and to prevent Iran-backed Houthi rebels from continuing to threaten commercial shipping in Red Sea. Sea.
Reporting from Tehran, Al Jazeera's Resul Sherdar said there have been more than 100 attacks on US military installations in the Middle East since Israel launched its assault on Gaza.
“Iran's position so far … has been quite clear. They say these attacks are not carried out or planned by Iran. They say Iran has allies across the region. However, these allies also make decisions based on their own decisions,” he said.
“The Iranians do not want a regional escalation. Iranian officials know that a direct military confrontation with Israel also means a war with the US that could be fatal for Iran.”
Colin Clarke, senior researcher at the Soufan Group, told Al Jazeera that these attacks show there has been a “regional war”.
“There is no doubt that. American troops were killed and the US will respond strongly either to Iran or against Iranian proxies in the various countries where they operate,” he said.
“Iran can choose to distance itself as much as it wants, but it is funding, training and arming these groups… The Biden administration will be under enormous pressure to show that the US is not going to stand by and watch its troops get killed from these Iranian – supported groups.
“The question now is what form that response will take,” Clarke said.
