"Coalition forces conducted a strike against a Daesh cell near Busayrah," Coalition Spokesman US Army Col. James Rawlinson said, using an Arabic acronym for ISIS, AFP reported on Monday.
Al-Busayrah is east of the Euphrates in eastern Deir ez-Zor governorate, approximately 100 kilometers upriver from the Iraqi border crossing at al-Qaim.
The river has served in Syria as a de facto demarcation line between the United States and Damascus which is backed by Russia and Iran.
"This operation eliminated five terrorists who played a key role in facilitating attacks across the region against security forces and innocent civilians," Rawlinson added.
ANALYSIS: Deir ez-Zor oil fields, ISIS, SDF, and coalition
Syria's state-run SANA news agency reported the airstrikes killed and injured civilians including women and children, citing unnamed local sources.
The strikes also damaged houses and caused panic because of their intensity, SANA claimed. Rudaw was unable to independently verify the US or Syrian claims.
A UK-based conflict monitor opposed to the Assad regime reported that the five killed were not of Syrian nationality in the early Sunday operation. The Syrian Observatory for Human Rights (SOHR) added that six more foreigners were targeted in the operation and killed over the past 24 hours.
The Syrian Democratic Forces (SDF) have served as the primary ground force in partnership with the US-led coalition. The SDF is predominately comprised of the Kurdish-led People's Protection Units (YPG); however, the SDF is a mixed umbrella force with various affiliations.
Working with local military councils in areas like Deir ez-Zor, the SDF along with the help of the coalition has sought to stabilize liberated towns. On Sunday, the SDF announced a new batch of fighters had graduated after receiving "political lessons and military training on medium weapons, snipers, combat tactics and methods of street fighting."
Busayrah near al-Mayadin and Deir ez-Zor city has large oil reserves, wells, infrastructure. The area has been a flashpoint through the ISIS and Syrian conflicts.
The SDF declared the military defeat of ISIS on March 23 after months of fighting and a siege in al-Baghouz that sits across the border from al-Qaim.
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