The attack, claimed by Daesh, comes as the Trump administration is planning to withdraw troops from Syria as the US president says Daesh has been defeated there. Turkey says it believes the assault will not change the US pull-out plan.
At least 16 people, including four US citizens, were killed in an attack on Wednesday in the Syrian city of Manbij, US officials and a war monitor in the region said.
"There are nine civilians dead, five from the SDF accompanying forces," the Britain-based Syrian Observatory for Human Rights (SOHR) said, referring to the YPG-led SDF, which the US backs in Syria in its fight against Daesh.
The blast killed two US soldiers, one defence agency intelligence specialist and an interpreter who was also a contractor, a US official said. At least three other US citizens were wounded
Manbij remains under the control of the PYD/YPG, the Syrian affiliate of the PKK terrorist organisation, which wrested control of the city from Daesh in 2016.
The attack occurred amidst Trump administration's plans to withdraw troops from Syria after the US president claimed to have eliminated Daesh from Syria.
US and Turkey recently started discussing creating a security-zone near the Turkish-Syrian border.
Daesh claimed responsibility for the attack on its propaganda site.
Amaq said an attacker had struck a foreign military patrol in a suicide attack.
The blast occurred as US military personnel were conducting a patrol of the city.
The US military command acknowledged the attack on Twitter.
CJTF-OIR is aware of open source reports regarding an explosion in Syria. Coalition forces conducted a routine patrol in Syria today. We are still gathering information and will share additional details at a later time.— OIR Spokesperson (@OIRSpox) January 16, 2019
"Turkey will continue the fight against Daesh and eliminate this terrorist group in Syria," Turkish President Recep Tayyip Erdogan said at a joint press conference with Croatian President Kolinda Grabar-Kitarovic in Ankara.
Erdogan said he does not believe US President Donald Trump will back down from his plans to pull out in the face of this attack, as this would mean victory for Daesh.
He added that the attack could be meant to dissuade the US from leaving Syria.
Daesh in Syria
"The caliphate has crumbled," US Vice President Mike Pence repeated claims of Daesh's defeat just hours after the attack on Wednesday.
Speaking at the state department, Pence said the militant network "has been defeated." Later, he released a statement condemning the attack but affirming the withdrawal plan.
"As we begin to bring our troops home, the American people can be assured, for the sake of our soldiers, their families, and our nation, we will never allow the remnants of ISIS [Daesh] to re-establish their evil and murderous caliphate - not now, not ever," he said.
Others, however, immediately pointed to the attack as a reason to reverse or adjust the withdrawal plan.
Senator Lindsey Graham, a Trump backer and prominent voice on foreign affairs on Capitol Hill, said during a committee hearing Wednesday he is concerned that Trump's withdrawal announcement emboldened the militants.
TRT World's Yasin Eken has more from the Turkey-Syria border.
TRT World spoke with analyst Yusuf Erim on the significance and the fallouts from the Manbij attack.