Eight women were slashed Sunday afternoon in a suspected knife attack at an amusement park pool in the western suburb of Akiruno, the Tokyo Fire Department said.

The victims, all around 20 years old, sustained only light injuries but were taken to a hospital for treatment. All were wounded in the buttocks, firefighters said.

The Metropolitan Police Department is investigating the attack, which occurred at a large wave pool at Tokyo Summerland, an amusement park with indoor and outdoor pools.

The wave pool was packed at the time, according to the park operator.

The amusement park is about 1.5 km southwest of JR Akigawa Station on the Itsukaichi Line.