A hand grenade stored in arms depot inside the Karachi Police Garden Headquarters exploded on Wednesday killing two police personnel and injuring two others, reported 24NewsHD TV channel.

The law enforcement personnel encircled the grenade blast site and ambulances shifted the injured to a hospital. 

Karachi SSP City Imran said that the police have launched an investigation into how this grenade exploded.

The martyred cops were identified as Shehzad and Sabir while Ali and Saeed sustained injuries.

Reporter Saud Bin Murtaza