Nine Ground Self-Defense Force members shot as many as 79 live rounds at one another by mistake in an exercise in Hokkaido on Monday, the GSDF said Tuesday.

A sergeant in his 30s and a leading private in his 20s sustained minor injuries when their equipment malfunctioned because they were using the incorrect ammunition. No one was hit by the bullets, according to the headquarters of the ground force's Northern Army.

The assault rifles used in the exercise were supposed to fire blanks and the GSDF will investigate how the live rounds got to be used.

The exercise, simulating an ambush, took place at the Shikaribetsu Training Area in the town of Shikaoi. All nine members involved in the exchange used Type 89 5.56-mm assault rifles, according to the GSDF.

In a typical exercise, bullets are handed to each troop just before the drill, and they are then loaded into their rifles. Troops should not have trouble distinguishing between live rounds and blanks because they look different, according to the GSDF.