Washington: Two U.S. service members and one American civilian were killed in a deadly attack in central Syria, which the United States has attributed to the Islamic State (IS). President Donald Trump warned of “very serious retaliation” following the incident.

The attack, near the historic city of Palmyra, also left a few U.S. service members wounded. U.S. Central Command confirmed the gunman was killed during the attack, while Syrian authorities reported injuries among members of Syria’s security forces.

Trump and Syrian leader react

In a social media post, Trump described the incident as “an ISIS attack against the U.S., and Syria, in a very dangerous part of Syria that is not fully controlled by them.” Speaking to reporters at the White House, he said Syria’s president, Ahmed al-Sharaa, was “extremely angry and disturbed” by the attack and affirmed that Syrian forces were cooperating with U.S. troops

Trump reiterated, “There will be very serious retaliation.” U.S. Defense Secretary Pete Hegseth added, “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.”

Details of the attack

The gunman, reportedly affiliated with ISIS ideology, opened fire at a military post’s gate. Syrian officials later said the attacker was a member of the Internal Security forces in the desert but did not hold a command position. Evaluations earlier this week had flagged his extremist leanings.

The casualties were airlifted to the Al-Tanf garrison, near the borders of Iraq and Jordan, for medical care. The attack marks the first U.S. fatalities in Syria since the fall of Bashar Assad a year ago.

US military presence and background

Syria's Interior Ministry spokesman Nour al-Din al-Baba added in an interview with state TV that some 5,000 members have joined Internal Security forces in the desert and they get evaluated on weekly basis. He added that three days ago, an evaluation was made for the attacker that concluded he might have extreme ideology and a decision was expected to be issued regarding his case on Sunday but “the attack occurred on a Saturday which is a day off for state institutions.”

U.S. officials made no reference in their statements to the gunman being a member of the Syrian security forces. When asked about the matter, a Pentagon official did not directly respond to the question but said, “This attack took place in an area where the Syrian President does not have control.”

The official spoke on condition of anonymity to discuss sensitive military issues.

The U.S. has hundreds of troops deployed in eastern Syria as part of a coalition fighting IS.

The U.S. had no diplomatic relations with Syria under Assad, but ties have warmed since the fall of the five-decade Assad family rule. Al-Sharaa, made a historic visit to Washington last month where he held talks with Trump. It was the first White House visit by a Syrian head of state since the Middle Eastern country gained independence from France in 1946 and came after the U.S. lifted sanctions imposed on Syria during the Assads’ rule.

Al-Sharaa led the rebel forces that toppled Bashar Assad in December 2024 and was named the country’s interim leader in January. Al-Sharaa once had ties to al-Qaida and had a $10 million U.S. bounty on his head.

Last month, Syria joined the international coalition fighting against the IS as Damascus improves its relations with Western countries following the ouster of Assad when insurgents captured his seat of power in Damascus.

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.

U.S. troops have maintained a presence in different parts of Syria — including Al-Tanf garrison in the southeast — to train other forces as part of a broad campaign against IS, and have been targeted in the past. One of the deadliest attacks occurred in 2019 in the northern town of Manbij when a blast killed two U.S. service members and two American civilians as well as others from Syria while conducting a patrol.

AP inputs