The U.S has moved its High Mobility Artillery Rocket System into southern Syria for the first time, according to a CNN report.

HIMARS is a truck-mounted rocket-launcher system capable of firing missiles to distances of up to 185 miles. Its movement to the Tanf area brings significant military power to an area recently in the spotlight due to several coalition strikes against pro-Syrian regime forces and the downing of a pro-regime drone by the United States on June 8.

This is the first time the U.S. has moved HIMARS into Syria, but not the first time it has used it in Syria. The U.S. is likely using the system in the country because of its long-range capability.

According to CNN, it was deployed via Turkey, across the border into northern Syria, to help the Syrian Democratic Forces battle the Islamic State group. HIMARS has also been used from Jordan and in Iraq to attack ISIS within the country.

One defense official said HIMARS was moved into Syria in response to pro-regime aggressions, while another said it was uncertain.

Regardless, U.S. defense officials maintain their actions against pro-regime forces is purely motivated by the need for self-defense.

"Those are self-defense strikes, and the commander on the ground has the authority to take whatever action necessary, and I support that," U.S. Defense Secretary Jim Mattis told the Senate Armed Services Committee on Tuesday.

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