During roughly two months in Syria, Marines fired more than 4,500 rounds in support of Kurdish and Syrian Arab forces, said the spokesman of the 11th Marine Expeditionary Unit.
The Marines were supporting the foreign troops as they tightened the noose on the Islamic State group's de facto capital of Raqqa, Maj. Craig Thomas said on Wednesday.
About 400 artillery Marines deployed to Syria during the 11th MEU's seven-month deployment aboard the Makin Island Amphibious Ready Group. The Marines were recently replaced by another Marine artillery unit, which has not been identified.
Marine Corps officials were tight-lipped on Wednesday when talking to reporters about the 11th MEU's contributions to operations in Syria and elsewhere. Thomas said that the number of artillery rounds the Marines fired in Syria was the one statistic he was allowed to share.
"It's an ongoing operation," Thomas said during a roundtable discussion. "We have another Marine unit that's there – to my knowledge, they have not released that name, so we'll let [Operation Inherent Resolve] do that. It's not exactly an established theater as Iraq or Afghanistan was."
Officials declined to say Wednesday whether the Marines came under attack while in Syria, deferring to the U.S. military command in charge of operations in Syria and Iraq.
The contingent of Marines came from across the Marine Air-Ground Task Force, include the battalion landing team, combat logistics battalion and aviation combat element, so they were prepared for the task, said Lt. Col. John Gianopoulos, the 11th MEU's operations officer.
"They studied what they were going into," Thomas said on Wednesday. "The Marines went into there were staffed with the right security elements, the right mobility, the right logistics, the right intel to be able to move around that battle space, successfully provide artillery fire and contribute to the mission."
Few other details about the 11th MEU's combat missions were available on Wednesday. Officials declined to say whether any aircraft from the amphibious assault ship Makin Island flew combat missions during the deployment.
In March, 11th MEU tweeted pictures showing AV-8B Harriers from the Makin Island being loaded with bombs. The pictures were quickly deleted after Marine Corps Times asked U.S. Central Command about them.
Officials acknowledged the 11th MEU conducted other missions during its deployment that they could not discuss publicly. "Some stuff we just simply cannot talk about," said Col. Clay Tipton, 11th MEU commander.
CNN reported in February that an MV-22B Osprey from the Makin Island crashed during a special operations forces raid in Yemen the month before. Navy SEAL William "Ryan" Owens, who died after being wounded in the raid, was posthumously advanced to senior chief petty officer.
On Wednesday, Thomas declined to discuss the Yemen raid, deferring questions to U.S. Central Command and Special Operations Command.