(CNN) When Marine Corps Staff Sgt. Louis Cardin of Temecula, California, was killed in an ISIS rocket attack in Iraq on March 19, the Pentagon announced the attack happened at a location called "Fire Base Bell." Now just days later that location has quietly been renamed -- with no public announcement.

The fire base is now called the "Kara Soar Counter Fire Complex."

The change is to make clear the base is only conducting defensive missions, one defense official said.

A fire base is generally defined as a small military area where troops fire artillery in support of advancing troops. But defense officials have repeatedly told CNN the artillery guns at the base are firing both defensive shells against ISIS attacks and planning to fire in support of Iraqi forces conducting offensive operations.

The Pentagon had been questioned by reporters if the fire base was opening the door to ground combat operations. Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff insisted that was not the case.

Read More