Donald Trump has threatened “serious retaliation” after three Americans were killed in an attack in Syria. Two US service members and one civilian were killed in an ambush the United States blames on the Islamic State terror group (ISIS). The US President said in a post on social media on Saturday: “This was an ISIS attack against the US, and Syria, in a very dangerous part of Syria, that is not fully controlled by them.” He added on Truth Social: “There will be very serious retaliation.”

Mr Trump told reporters at the White House that Syria’s president, Ahmed al-Sharaa, was “devastated” at what had happened and stressed Syria was fighting alongside US troops. In his post, Mr Trump said his Syrian counterpart was “extremely angry and disturbed by this attack”. US Central Command said three service members were also wounded in the ambush by a lone IS member in central Syria. The gunman was killed, according to the US military.

The US President said the three who were wounded “seem to be doing pretty well”.

US Defence Secretary, Pete Hegseth, posted on X: “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.”

The Pentagon’s chief spokesman, Sean Parnell, said the civilian killed was an interpreter. He said the attack had targeted soldiers involved in an ongoing counter-terrorism operation in the region and it is being investigated.

The shooting happened near Palmyra, according to the state-run SANA news agency, which earlier said two members of Syria’s security force and several US service members had been wounded.

Casualties were taken by helicopter to the al-Tanf garrison near Syria’s border with Iraq and Jordan.

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

But Syria’s Interior Ministry spokesman, Nour al-Din al-Baba, said a gunman linked to IS opened fire at the gate of a military post.

He added Syrian authorities were looking into whether the gunman was an IS member or only carried its extreme ideology. He denied reports which suggested the attacker was a security member.

Hundreds of troops have been deployed by the US in eastern Syria as part of a coalition fighting IS.

Relations between Syria and the US have warmed since the fall of the Assad family, which ruled for 50 years.

Mr Al-Sharaa paid a historic visit to Washington last month where he held talks with Mr Trump.

It was the first White House visit by a Syrian head of state since the Middle East country gained independence from France in 1946. It also came after the US lifted sanctions imposed on Syria during the Assad regime.

Mr Al-Sharaa led the rebel forces which toppled the former president, Bashar Assad, in December last year. He was named the country’s interim leader in January.

In November, Syria joined the international coalition fighting against IS as Damascus continued to improve relations with Western countries after the ousting of Assad.

IS was defeated on the battlefield in Syria in 2019 but the group’s sleeper cells still carry out deadly attacks in the country. The United Nations says the group still has between 5,000 and 7,000 fighters in Syria and Iraq.