The United States Marine Corps announced this week that it had authorized military police officers to bring their privately owned firearms onto bases, a rule change that senior officers said was hastened by fatal shootings at two Navy installations in the past month.

About 3,200 qualified law enforcement officers are eligible to arm themselves for their personal protection, but not in the performance of their official duties under the new rule, Captain Joseph Butterfield, a U.S.M.C. spokesman, said on Thursday. They are required to have a concealed carry permit for the firearms.

Previously, only service weapons could be carried by members of the group — which includes military police, criminal investigators and civilian law enforcement officers who work for the Marines at some bases — solely as part of their duties.

The Marine Corps said in a memo on Tuesday that the rule change had already been in the works when the “tragic events” — a Dec. 4 shooting at Pearl Harbor Naval Shipyard and a Dec. 6 shooting at Naval Air Station in Pensacola, Fla. — convinced its leadership to accelerate the timetable.