OSAKA — A 17-year-old student was injured Saturday in what he claimed was an attack by a knife-wielding man in his prefectural high school, but police said the wound may have been self-inflicted because his wound apparently fails to fit the student's depiction of the attack.

The student, a senior at Osaka Prefectural Takaishi High School in the city of Takaishi, told police earlier that a man entered the school around 11:30 a.m. and fled after stabbing him in the right arm on a second-floor staircase inside the main building, they said.

The student also told the police that the man was around 30 years old, about 170 cm tall, and wearing a navy blue T-shirt, jeans and a black cap, they said.

The school was closed Saturday, but some students and teachers were there for club activities, they said.

The school is about 15 km north of Kansai International Airport.