The US military has identified three of the four Americans killed during a suicide bombing in Syria claimed by the Islamic State (IS) group.
Jonathan Farmer, a soldier, Shannon Kent, a sailor, and civilian Scott Wirtz died in Manbij on Wednesday as a result of wounds from the blast.
IS said a militant had detonated an explosive vest next to an American patrol in the Kurdish-held town.
US forces are operating around Manbij to back Kurdish and Arab forces.
The fourth victim of the explosion is an unnamed contractor, according to US Central Command.
At least 15 people were killed in the blast, and another three US soldiers were wounded.
Mr Farmer, 37, of Florida, served as Army chief warrant officer.
He was a recipient of the Army Achievement Medal, Bronze Star Medal, and Purple Heart, among other decorations, the Marine Corps Times reported.
Ms Shannon Kent, 35, of New York, was a Navy chief cryptologic technician.
In a statement, Navy Cmdr Joseph Harrison described Ms Kent as “a rockstar” and “leader to many in the Navy Information Warfare Community”.
The Pentagon did not release Mr Wirtz’s age, but he was a civilian from Missouri working as an operations support specialist at the Defense Intelligence Agency.
They were the first US casualties following President Donald Trump’s recent order to pull the military from Syria.
The investigation into the attack is ongoing.
On Wednesday, a suicide bomber using what the Pentagon called an “improvised explosive device” attacked a restaurant near Manbij’s main market.
The restaurant, the Palace of the Princes, was a favourite among US troops – even playing host to Senators Lindsey Graham and Jeanne Shaheen, the New York Times reported.
The troops were to meet members of the Manbij Military Council at the restaurant when the attack occurred, a witness told Reuters news agency.
CCTV footage from a nearby shop shows a large fireball engulfing several people standing on the street outside.
US soldiers were evacuated by helicopter following the attack, according to local media.
What is the situation in Syria?
The US-led coalition announced it destroyed an Islamic State group “command and control facility” on Thursday in a mosque in Safafiyah, Syria.
“ISIS continues to violate Law of Armed Conflict and misuse protected structures like hospitals and mosques, which cause a facility to lose its protected status,” said a US military statement, using another acronym for IS.
Last month, Mr Trump announced that the US would begin pulling out all its 2,000 troops from Syria because IS had been “defeated”.
Opponents of the withdrawal stressed that although IS now control only 1% of the territory they overran five years ago, the group had not disappeared entirely.
IS fighters have been driven out of almost all of eastern Syria. A recent US report said some 14,000 remaining IS militants in Syria and neighbouring Iraq were expected to use guerrilla tactics as they attempt to rebuild their network.
US Vice-President Mike Pence said he and President Trump condemned the attack in Manbij but reiterated that the withdrawal plan would continue as the US had “crushed the [IS] caliphate and devastated its capabilities”.