WASHINGTON — US President Donald Trump on Saturday warned of “very serious retaliation” after two American service members and one US civilian were killed in an attack in central Syria that Washington blamed on the Islamic State group.

In a social media post, Trump said the assault was carried out by IS in “a very dangerous part of Syria” and stressed that the United States would respond forcefully. “There will be very serious retaliation,” he wrote.

US Central Command said the attack was carried out by a lone IS gunman and left three additional US service members wounded.

The military said the attacker was killed. Trump later said the wounded Americans were recovering and “seem to be doing pretty well.”

A Pentagon spokesman identified the civilian killed as a US interpreter. Syrian state media reported that members of Syria’s security forces were also wounded in the shooting.

The attack took place near the historic city of Palmyra, according to Syria’s state-run SANA news agency.

Casualties were evacuated by helicopter to the US-led coalition’s al-Tanf garrison near the borders with Iraq and Jordan.

Trump said Syria’s president, Ahmed al-Sharaa, was “extremely angry and disturbed” by the attack and described him as “devastated by what happened.”

He added that Syrian forces were fighting alongside US troops against IS.

Syria’s Interior Ministry said the gunman opened fire at the gate of a military post. A ministry spokesman later said the attacker was a member of the Internal Security forces in the desert region but did not hold a command role.

Syrian authorities said they had previously flagged concerns over the attacker’s extremist ideology and were due to review his case.

A Pentagon official said the shooting occurred in an area not fully under the Syrian president’s control.

US Defense Secretary Pete Hegseth said in a post on X that any attack on Americans would be met with decisive force.

“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,” he said.

The incident marked the first fatal attack on US forces in Syria since the fall of former president Bashar Assad last year.

The United States maintains several hundred troops in eastern and central Syria as part of an international coalition fighting IS.

Although IS was territorially defeated in Syria in 2019, the group continues to carry out attacks through sleeper cells. The United Nations estimates IS still has between 5,000 and 7,000 fighters across Syria and Iraq.

Relations between Washington and Damascus have warmed since Assad was toppled in late 2024.

Al-Sharaa, who led the rebel coalition that ousted Assad, visited Washington last month for talks with Trump following the lifting of US sanctions imposed during Assad’s rule. — Agencies