BAGHDAD _ Islamic State claimed a suicide bombing that killed four U.S. service members as well as civilians and Kurdish militia members in the northern Syria city of Manbij on Wednesday, according to a U.S. official.
It was the deadliest day for U.S. forces in the Syrian war and comes after President Donald Trump announced he would withdraw troops from the nation based on his claim that Islamic State had been all but vanquished.
The official, who also said another three U.S. service members had been wounded, spoke on the condition he not be identified. A spokesman for the U.S.-led coalition in Syria confirmed there were fatalities but declined to provide details.
"U.S. service members were killed during an explosion while conducting a routine patrol in Syria today," Col. Sean Ryan said in a statement. "We are still gathering information and will share additional details at a later time."
Manbij is controlled by a Syrian Kurdish militia known as the People's Protection Units, or YPG, which is backed by the U.S. and has been conducting joint patrols with American troops in the city.
It was during one of these patrols that the Islamic State attacker, nicknamed Abu Yassin al-Shami according to a statement by the extremist group, approached a group of U.S.-led coalition personnel and Kurdish militants gathered near a restaurant about 1 p.m. local time and detonated a suicide belt.
Islamic State claimed nine coalition personnel were killed or wounded, along with a number of Kurdish fighters.
The number of dead and wounded had yet to be confirmed, but local media outlet Hawar News quoted officials in Manbij saying a number of YPG fighters as well as 13 civilians were killed. The Syrian Observatory for Human Rights, a pro-opposition monitor that is based in Britain but employs a network of activists in Syria, put the death toll at 16.
Local media outlet Hawar News broadcast a video depicting the moment of the blast. It shows people walking through a marketplace area in the center of Manbij when an explosion blasts out of one of the storefronts.
Two pedestrians, engulfed in the flames of the blast, quickly fall to the ground while another one approaching the restaurant turns around and runs away.
White House press secretary Sarah Sanders said Trump had been fully briefed on the incident.
"We will continue to monitor the ongoing situation in Syria," she said.
Activists reported a heavy security presence in the immediate aftermath of the attack, with helicopters arriving near the area to evacuate casualties while a joint U.S.-French investigative team cordoned off the site of the explosion.
"The restaurant is in the center of town, and it's normally a crowded area," said Abu Ahmad, an activist in Manbij. He gave a nickname for reasons of security.
The attack comes as Trump ordered a withdrawal of some 2,000 troops from Syria while ceding the fight to destroy what he said were the remnants of Islamic State to Turkey.
Vice President Mike Pence on Wednesday repeated Trump's claim that Islamic State was no longer a threat.
"Thanks to the leadership of this commander in chief and the courage and sacrifice of our armed forces we're now actually able to begin to hand off the fight against ISIS in Syria. ... We are bringing our troops home," Pence said in a speech to a group of U.S. ambassadors at the State Department.
"The caliphate has crumbled and ISIS has been defeated," said Pence, using an acronym for the militant group.
Trump's decision, taken against the recommendations of many of his foreign policy and military advisers, would leave the Kurds to face Turkey, which views the YPG as a proxy force for the Kurdish insurgency it has been fighting for decades.
Many have criticized the move as an outright abandonment of what has been a dependable U.S. ally in the fight against the extremist group. Others say it would give Islamic State the space it needs to reconstitute itself after losing all of the territories it once held in its grip.
Yet it's unclear how Wednesday's bombing would affect the pace of the withdrawal, with Trump changing the timeline of the pullout in various statements over the last week.
Another question is who is to blame for the infiltration of an Islamic State fighter into Manbij, a city protected by the coalition as well as the YPG, with Turkish-backed Syrian rebels as well as Syrian government troops on its perimeter.
In a statement, Rep. Michael McCaul of Texas, the top Republican on the House Foreign Affairs Committee, said: "Today's deadly bombing targeting our troops in Syria is a reminder that ISIS still has the capacity to carry out attacks."
"I strongly urge the president to forcefully respond and ensure we do not withdraw our troops until ISIS is completely destroyed," McCaul said.
