Tokyo: A 15-year-old Japanese schoolgirl has been arrested on suspicion of murdering a classmate and dismembering her body.

The suspect, whose name has not been released, admitted strangling the victim and severing her head and left hand, Kyodo news agency reported on Sunday.

She allegedly delivered blows to the head of 15-year-old Aiwa Matsuo with a metal instrument before strangling her in the city of Sasebo, in Nagasaki Prefecture, south-west Japan.

The victim's body was found on a bed in the suspect's apartment early on Sunday and investigators discovered tools nearby, reports said.