American military personnel can now carry privately owned, concealed weapons at defense facilities, the Pentagon said in recent directive. The decision was taken following a spate of fatal shootings in the last 10 years on U.S. military bases.

The directive was issued Friday and was reportedly approved by Deputy Secretary of Defense Robert Work. Personnel not less than 21 years of age can apply to carry concealed firearms. Commanders with ranks O-5 and above “may grant permission to DoD [Department of Defense] personnel requesting to carry a privately owned firearm [concealed or open carry] on DoD property for a personal protection purpose not related to performance of an official duty or status,” the directive read.

“Written permission will be valid for 90 days or as long as the DoD Component deems appropriate and will include information necessary to facilitate the carrying of the firearm on DoD property consistent with safety and security, such as the individual's name, duration of the permission to carry, type of firearm, etc.,” it said.

Previously, military officials were not allowed to carry personal weapons on bases. However, following a series of deadly shootings at military bases led authorities to change the policy. It was after the 2009 shooting at Fort Hood in Texas — where former Army Maj. Nidal Hasan gunned down 13 people — that officials worked toward authorizing personnel to carry their personal firearms at military installations.

Last July, four Marines and a sailor were killed in attacks at a recruiting station and Navy reserve center in Chattanooga, Tennessee. Authorities reportedly suspected international terrorism influenced the attack.