Russian emergency officials say an ammunition explosion at a military installation in southern Russia Tuesday killed six soldiers.

Another 12 soldiers were injured in the incident at the Ashuluk base in the Astrakhan region.

Officials say the explosion probably occurred as the soldiers were disposing of old ammunition. The exact cause is yet to be determined.

Tuesday's explosion follows a pair of mishaps at Russian ammunition depots earlier this year. Explosions and fires at the facilities have been blamed on regulatory corner cutting and negligence.