A number of US troops have been killed in a reported suicide bomb attack in Syria claimed by the Islamic State group, the US military says.
IS said one of its militants detonated an explosive vest next to a US patrol in the Kurdish-held town of Manbij.
A Kurdish news agency reported that three US soldiers, a local security officer and nine civilians died.
US troops are in Manbij to back Kurdish and Arab fighters who have driven IS out of almost all of eastern Syria.
Wednesday’s explosion occurred at a restaurant near Manbij’s main market.
The Syrian Kurdish Hawar News Agency (ANHA) reported that four US soldiers were seen being evacuated by a helicopter afterwards.
Later, a spokesperson for the US-led multinational coalition against IS tweeted: “U.S. service members were killed during an explosion while conducting a routine patrol in Syria today.”
“We are still gathering information and will share additional details at a later time.”
Reuters news agency meanwhile cited a US official as saying that four soldiers were killed and three others wounded.
Last month, President Donald 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 controlled only 1% of the territory they overran five years ago, the group had not disappeared entirely.
A recent US report said there were still as many as 14,000 IS militants in Syria and even more in neighbouring Iraq – and that they were expected to shift to guerrilla tactics in an attempt to rebuild their network.
Syrian Kurds also fear that Manbij and other towns they control near the border with Turkey might come under attack by the Turkish military, which wants to clear them of the Kurdish People’s Protection Units (YPG) militia.
The Turkish government considers the YPG an extension of the banned Kurdistan Workers’ Party (PKK), which has fought for Kurdish autonomy in Turkey for three decades. However, it denies any direct organisational links to the group.