An ISIS operative was killed Thursday in a rare raid in northeast Syria known to be held by pro-government forces, a U.S. defense official told Fox News. 

The target was located in the city of Qamishli in northeast Syria near the Turkish border, a defense official confirmed. 

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The ISIS operative killed in the raid was named Abu Hayel, also known as Rakkan Wahid al-Shammri, while one other unidentified ISIS fighter was also wounded. 

A U.S. defense official confirmed for Fox News that there were no U.S. casualties and no operational reports of civilian casualties.

Islamic State militant holds ISIS flag in a desert setting

A masked Islamic State soldier poses holding the ISIS flag in 2015. (Pictures from History/Universal Images Group via Getty Images)

The purpose of the operation remains unclear. 

Though the U.S. has conducted raids in Syria targeting ISIS members, the Thursday raid is believed to be the first conducted in an area known to be held by forces loyal to President Bashar al-Assad, reported Reuters. 

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Syrian state news said the raid was carried out by airborne forces with the aid of Syrian Kurdish forces, and claimed that one civilian was killed while others were captured.

The U.S. has been fighting ISIS in Syria since 2015 and continues to maintain a presence in the country with some 1,000 soldiers stationed there.