The U.S. is sending a detachment of Marines to Iraq following a deadly attack on a coalition base in northern Iraq that left one Marine dead and eight more injured.

The Marines and sailors headed to Iraq are with the 26th Marine Expeditionary Unit, according to the U.S. task force running the war against the Islamic State group . The detachment will augment Marines and sailors already fighting ISIS, officials said Sunday .

It is not immediately clear how many Marines and sailors from the 26th MEU are deploying to Iraq or whether they are replacing any of the Marines injured in Saturday's rocket attack.

The 26th MEU is currently deployed to the 5th Fleet area of operations with the Kearsarge Amphibious Ready Group. The more than 4,000 Marines and sailors with the blue-green team have been deployed since October.

News of the Marines headed to Iraq comes one day after Staff Sgt. Louis Cardin, who was deployed with the 26th MEU , was killed by a rocket attack on a coalition fire base near Makhmur, Iraq. ISIS has launched mustard gas attacks in that area. Kurdish fighters also stopped an attempted attack there in November when the terror group tried to use mortar rounds filled with chlorine gas .

Makhmur is also where the Nineveh Operations Center is located. It is a primary base from which the U.S. can support Iraqi forces when they eventually try to retake Mosul, which fell to the Islamic State in June 2014. Iraqi military leaders plan to deploy about 4,500 troops to the area for the upcoming operation.

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Hundreds of Marines have been quietly deploying to Iraq over the past 16 months to assist Iraqis fighting to retake territory from ISIS militants.