United States President Donald Trump has pledged to pursue “serious retaliation” against the armed group ISIL (ISIS) after an ambush in central Syria killed two US service members and one civilian interpreter, also from the US.

The attack on US forces on Saturday was the first to inflict casualties since the fall of Syrian President Bashar al-Assad a year ago.

Three additional US military members were injured in the attack, as well as at least two Syrian troops, according to government and media reports.

In a social media post, Trump said he had received confirmation that the injured US soldiers were “doing well”.

He, however, warned that there would be serious consequences for what he described as an ISIL (ISIS) attack.

“This was an ISIS attack against the U.S., and Syria, in a very dangerous part of Syria, that is not fully controlled by them,” Trump wrote. “The President of Syria, Ahmed al-Sharaa, is extremely angry and disturbed by this attack. There will be very serious retaliation.”

His remarks echoed those of Secretary of Defense Pete Hegseth, who likewise promised to take severe action against anyone who attacked US service members.

“Let it be known, if you target Americans — anywhere in the world — you will spend the rest of your brief, anxious life knowing the United States will hunt you, find you, and ruthlessly kill you,” Hegseth wrote on social media.

Conducting ‘counter-terrorism operations’

Saturday’s attack was first announced by US Central Command, also known as CENTCOM.

It characterised the attack as an “ambush” carried out by a lone ISIL gunman, who was subsequently “engaged and killed”. Hegseth later confirmed that the perpetrator “was killed by partner forces”.

The attack took place near Palmyra in Syria’s central Homs region, according to Pentagon spokesperson Sean Parnell.

“The attack occurred as the soldiers were conducting a key leader engagement,” he wrote in a statement. “Their mission was in support of on-going counter-ISIS/counter-terrorism operations in the region.”

Tom Barrack, the US ambassador to Turkiye, meanwhile, described the incident as a “cowardly terrorist ambush targeting a joint U.S.–Syrian government patrol”. He noted there were “Syrian troops wounded in the attack” and wished them a “speedy recovery”.

But the details about the attack and the individuals involved remain unclear.

CENTCOM indicated the US government would withhold identifying information about the late US soldiers and their units “until 24 hours after their next of kin have been notified”.

The incident remains under “active investigation”, according to the US Department of Defense.