A suicide attack claimed by the Islamic State group killed 15 people including a US serviceman Wednesday in the northern Syrian city of Manbij near the Turkish border, a monitor said.
Nine civilians and five US-backed fighters were among the dead in the attack on a restaurant in the flashpoint city, the Syrian Observatory for Human Rights said, reports AFP.
Rubble littered the outside of the eatery in the city centre, footage from a Kurdish news agency showed, and its facade was blackened by the blast.
The Britain-based Observatory, which relies on a network of sources in Syria, said it was the first such suicide attack in the city against the US-led coalition fighting IS in 10 months.
The bombing came as Kurds who control a large swathe of northern Syria rejected a Turkish plan to set up a "security zone" on the Syrian side of the border.
Almost eight years into Syria's civil war, Turkey has repeatedly threatened to attack Syrian Kurdish fighters it views as "terrorists" on its southern flank.
Washington, which has relied heavily on the Kurds in its campaign against IS in Syria, has sought guarantees for their safety after President Donald Trump suddenly announced a US troop pullout last month.
On Tuesday, Turkey's President Recep Tayyip Erdogan said Ankara would set up a "security zone" in northern Syria following a suggestion by Trump.
The planned buffer would embrace a large swathe of the autonomous region the Kurds have established in northern and northeastern Syria.
Senior Kurdish political leader Aldar Khalil said any Turkish deployment in Kurdish-held areas was "unacceptable".