Marines arrive in Syria to provide artillery support in fight against ISIS The Marines will provide artillery support to local forces.

 -- A contingent of several hundred Marines has arrived in Syria to provide artillery support to U.S.-backed Syrian rebels preparing to retake Raqqa, ISIS's de facto capital in Syria, according to a U.S. military official.

The artillery battery from the 11th Marine Expeditionary Unit has been arriving in Syria over the last couple of weeks to establish a fire base for their howitzer artillery, according to the military official. The battery's M777 howitzers are capable of hitting targets up to 20 miles away.

The number of Marines associated with the battery and support elements number "more than several hundred," said the official. The U.S. military is authorized to have up to 503 American troops inside Syria to advise and assist the local Syrian Democratic Forces (SDF) fighting ISIS.

The Marines will provide artillery support to the local forces, which are currently working to isolate the city of Raqqa in advance of a full offensive on the city.

American military officials have often stated that the SDF will need additional combat power if they are to press into Raqqa, where ISIS has already established elaborate defenses. The Marine artillery would be able to provide additional combat support for SDF fighters in and around Raqqa.

The deployment to Syria is similar to one in early 2016, when 200 Marines established a fire base in northern Iraq to support Iraqi troops pushing northward toward Mosul. That Marine unit was subsequently replaced by an Army unit, the military official said. Depending on how the future fight for Raqqa progresses, it may not be necessary to replace the Marine artillery battery, the official added.

The Marines' deployment to Syria was first reported Wednesday by The Washington Post.

The military official said the deployment to Syria had been long-planned, but that the final decision to send them was only made recently by military commanders at U.S. Central Command. It did not require a presidential authorization since they were already in the Middle East and the movement of troops into Syria was not associated with the proposals presented to President Donald Trump last week to accelerate the fight against ISIS.

The Marines now in Syria are part of a larger force of 2,200 Marines deployed to the Middle East aboard the amphibious vessels the USS Makin Island, USS Comstock and USS Somerset.

The military official said the Marines will not count toward the troop cap in Syria because they are on a temporary deployment. American troops serving less than 120 days in Iraq and Syria are not counted as part of the force levels authorized by the White House for each country.

The Marines' arrival in Syria is the second time this week that additional American forces have arrived in Syria. Over the weekend, a small force of Army Rangers was deployed to the northwest city of Manbij to provide what a Pentagon spokesman called a "visible sign of deterrence." Their presence is intended to prevent the possibility of Turkish troops and U.S.-backed Kurdish forces attacking each other.