Hiroshima officials have begun using a drone to help survey the deterioration of the Atomic Bomb Dome in the western Japanese city.

Officials began the first full-scale survey of the UNESCO World Heritage site to use a drone on Monday.

The aerial vehicle slowly flew about 4 meters from the outer wall and took photos every two seconds.

Built in 1915, the structure was almost destroyed by the blast wave and heat from the explosion of the atomic bomb that was dropped on the city on August 6, 1945.

The city surveys the dome, which stands in Peace Memorial Park, every three years to monitor the deterioration of the exterior's bricks and mortar.

City officials say thousands of photos taken by the drone will be used to create 3D images, which would enable more precise inspections of the outer wall than doing so with the human eye.

They also say this avoids having to erect scaffolding that obstructs visitors' view of the dome.

City official Nakata Makoto says the drone-based survey will make it easier to preserve the images of the dome as a digital archive.

He also expressed hope that the digital data will help people truly grasp the reality of the atomic bombing and keep it in their hearts.

The survey will run through September 6.