The blasts at the arms depot in Sihala area, located about 20 km from the garrison city of Rawalpindi, were believed to be accidental in nature, TV news channels reported.
The blasts damaged a building and triggered a fire. Army troops and policemen cordoned off the area and prevented people and media from approaching the arms depot.
Witnesses said they had seen several ambulances leaving the arms depot and going to a nearby military hospital.
Police officials told the media that at least two persons were injured. No further details were immediately available.
Several government buildings, including a police training centre and facilities linked to Pakistan's nuclear programme, are located in the Sihala area which is heavily guarded.