An air strike on Tuesday by a U.S.-led coalition fighting Islamic State mistakenly killed 18 members of the Syrian Democratic Forces (SDF) south of the city of Tabqa, Syria, the Pentagon said on Thursday.
"The strike was requested by the partnered forces, who had identified the target location as an ISIS fighting position," it said in a statement. "The target location was actually a forward Syrian Democratic Forces fighting position."
The SDF is a US-allied coalition of Syrian Kurds and Arabs.
A Pentagon news release did not further identify the forces that requested the airstrike, which occurred as part of the coalition's air support of an offensive to free al-Raqqa, Islamic State's de facto capital in Syria.
The statement expressed the coalition's "deepest condolences" to SDF members and their families.
The SDF "have expressed a strong desire to remain focused on the fight against ISIS despite this tragic incident," the statement said.
The coalition is assessing the cause of the incident and will implement appropriate safeguards to prevent similar incidents in the future, it added.
Meanwhile on Thursday the Syrian army claimed that an airstrike late on Wednesday by the U.S.-led coalition had hit poison gas supplies belonging to the Islamic State group, releasing a toxic substance that killed "hundreds including many civilians."
The U.S.-led coalition has since denied the report.
Later on Thursday, Assad claimed in an AFP interview that a chemical attack last week in Syria's northern Idlib province, in which more than 80 were killed, was a compelete fabrication.
The Syrian leader went on to say that while Al-Qaida had been behind the assault, the U.S. blamed the incident on the Syrian military "to have a pretext for the attack," referring to America's missile strike on a Syrian regime air base.
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