US and UK defense officials on Saturday released the names of the two troops who were killed this week in an improvised explosive device attack in the Manbij area of Syria.
US Army Master Sgt. Jonathan Dunbar, 36, of Austin, Texas, and British soldier Sgt. Matt Tonroe died as a result of Thursday's explosion, the defense officials said.
Dunbar died Friday, a day after the blast, the Pentagon said.
The UK Ministry of Defence has said Tonroe was embedded with US forces on a counter ISIS operation when the attack occurred.
The explosion also injured five others, the US-led coalition in Syria has said.
The coalition said details about the incident are being withheld pending further investigation.
Dunbar was assigned to the headquarters of US Army Special Operations Command at Fort Bragg, North Carolina, the Pentagon said.
Tonroe was "deployed numerous times on operations to Afghanistan and the Middle East," the UK ministry said.
"His distinguished service reflected a man that was happiest when professionally tested on operations," a ministry statement said. "He relished responsibility, the opportunity to contribute and when the time came, to lead. He was a natural in this role."
The United States maintains about 2,000 troops in Syria, who mostly work with local allies fighting ISIS.
President Donald Trump said Thursday that the United States would "be coming out of Syria like very soon," just hours after the Pentagon highlighted the need for US troops to remain in the country for the immediate future.