Two US soldiers and a US civilian interpreter have been killed in Syria in an ambush by an Islamic State (IS) gunman, the US Central Command (Centcom) has said.

Officials said three other service members were injured in the attack, during which the gunman was engaged and killed. Syria's state news said two Syrian service personnel were also injured.

US President Donald Trump wrote on social media that it was an ISIS attack against the US and Syria and said there would be a very serious retaliation. The Syrian government has issued a statement condemning the attack.

The identities of those killed are being withheld for 24 hours until their next of kin have been informed, Centcom said.

In a post on X, Centcom, which directs American military operations in Europe, Africa and the Indo-Pacific, noted the attack was the result of an ambush by a lone ISIS gunman, while a Pentagon official suggested the attack was likely to be carried out by the Islamic State group.

The UK-based Syrian Observatory for Human Rights indicated that the attacker was a member of the Syrian security force.

No group has claimed responsibility for the attack, and the identity of the gunman has yet to be revealed.

The ambush took place in Palmyra while the soldiers were conducting a key leader engagement, according to Pentagon spokesperson Sean Parnell.

He added the attack is under investigation. A Pentagon official indicated that the incident occurred in a region where the Syrian president does not maintain control.

Trump added that the three injured US soldiers were doing well.

US Defence Secretary Pete Hegseth remarked: 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.

Syria's Foreign Minister condemned the attack and extended condolences to the victims' families.

Tom Barrack, US ambassador to Turkey and special envoy for Syria, said: I strongly condemn the cowardly terrorist ambush targeting a joint US–Syrian government patrol in central Syria. We remain committed to defeating terrorism with our Syrian partners.

US troops have been present in Syria since 2015 to assist in training local forces as part of the international campaign against IS.