Washington DC, 14 December 

US President Donald Trump on Saturday (local time) pledged "very serious retaliation" after an ISIS gunman killed two US soldiers and one civilian interpreter in an ambush in Syria, calling the attack a strike against both the United States and Syria.

Speaking at the White House, the president described the victims as "three great patriots" and characterised the incident as an assault on both Washington and Damascus.

"This was an ISIS attack on us and Syria," he told reporters. "We mourn the lost and we pray for them and their parents and their loved ones."

Asked if the US would respond, Trump was unequivocal: "Yes, we will retaliate."

He repeated the warning on Truth Social, writing, "There will be very serious retaliation. We mourn the loss of three Great American Patriots in Syria--two soldiers and one civilian interpreter.

Likewise, we pray for the three injured soldiers who, it has just been confirmed, are doing well."

US Central Command (CENTCOM) confirmed that the attack occurred on 13 December during counter-terrorism operations near Palmyra. The lone gunman was engaged and killed by US and partner forces. Three other US soldiers were wounded but are recovering.

The identities of the deceased will be withheld for 24 hours until next of kin are notified.

Trump also said Syria's new president, Ahmed al-Sharaa, was "extremely angry and disturbed" by the attack, which occurred in "a very dangerous part of Syria" not fully under government control.

The US has approximately 900 troops deployed in Syria as part of ongoing operations against Islamic State militants.

The shooting occurred weeks after Syria's interim president, Ahmed al-Sharaa, held talks with Trump at the White House. Al-Sharaa came to power after the downfall of Bashar al-Assad's government last year. Assad later fled to Russia, where he was granted asylum, and has vowed to continue opposing rebel forces. Al-Sharaa, a former al-Qaeda member who was previously detained by US forces in Iraq, had his global terrorist designation lifted by Trump ahead of their meeting.