More than 400 Marines are headed home after providing artillery support for allied forces that fought to retake the former Islamic State capital of Raqqa, Syria, officials announced on Thursday.

Marines and sailors with 1st Battalion, 10th Marines arrived in Syria in September to replace another Marine artillery unit that had been supporting Syrian fighters, which battled to take Raqqa from June 6 to Oct. 20, the U.S.-led task force in Iraq and Syria said in a news release.

The fight was so intense that the Marines burned out the barrels of two M777 155 mm howitzers, Army Sergeant Major John Wayne Troxell, the senior enlisted adviser to chairman of the Joint Chiefs of Staff Gen. Joseph Dunford, told reporters in October.

“With a 155 mm artillery battery in the fight, their mission was to deny and disrupt ISIS from gaining ground or moving from their defensive positions,” Marine Lt. Col. Jon O’Gorman, chief of fires for Combined Joint Task Force – Operation Inherent Resolve, said in Thursday’s news release. “These Marines rained relentless and highly accurate firepower on the enemy.”

In the end, the Syrian Democratic Forces defeated more than 2,500 ISIS fighters believed to have been in Raqqa. Now that the city has been retaken, the artillery Marines have been ordered to return home, and a replacement unit will no longer deploy to Syria, the news release says.

“The departure of these outstanding Marines is a sign of real progress in the region,” Brig. Gen. Jonathan Braga, director for operations in Iraq and Syria, said in the news release. “We’re drawing down combat forces where it makes sense, but still continuing our efforts to help Syrian and Iraqi partners maintain security.”