The international coalition has killed as many as 150 "Islamic State of Iraq and Syria" (ISIS) fighters in an operation in the middle Euphrates River Valley in Syria, AFP reported Tuesday (January 23rd).

According to a coalition statement, the airstrikes took place Saturday near al-Shafah, in Deir Ezzor province, on an ISIS headquarters where the group appeared to have been "massing for movement".

"The precision strikes were a culmination of extensive intelligence preparation to confirm an ISIS headquarters and command and control centre in an exclusively ISIS-occupied location in the contested middle Euphrates River Valley," the statement read.

While ISIS has lost most of the terrain it once controlled in Syria, the group remains entrenched in pockets along the middle Euphrates River Valley.

The coalition said the Syrian Democratic Forces (SDF) had assisted in target observation prior to the strike.

"The combination of intelligence and continuous eyes on the target ensured no accidental engagement of non-military personnel," the statement read.

"Our SDF partners are still making daily progress and sacrifices, and together we are still finding, targeting and killing ISIS terrorists intent on keeping their extremist hold on the region," Maj. Gen. James Jarrard said.