Image copyright AFP Image caption Anna Iriyama suffered a fractured little finger and lacerations to her head

A man has been sentenced to six years in jail for attacking two members of popular Japanese girl band AKB48 with a saw at a fan event last year.

Satoru Umeta, 24, was convicted of assaulting Rina Kawaei and Anna Iriyama, now both 19, along with a male staff member.

All three were seriously injured after Umeta lunged forward to slash them with a saw fitted with box cutter blades.

AKB48 holds the Guinness Record for being the world's largest pop group.

"The fear the victims had during the event, where they were meeting with fans, and the mental damage were significant," judge Takehiko Okada said, according to AFP news agency.

Umeta's lawyers said their client had shown signs of schizophrenia, AFP reported. Judge Okada said Umeta was frustrated over his unemployment, Kyodo news agency said.

The number 48 in AKB48 reportedly refers to the original number of singers in the group, although it has since expanded and now numbers about 140 rotating members, ranging from their teens to early 20s.

The group, which was founded in 2005, is hugely popular in Japan and other Asian countries.

Image copyright AFP Image caption Rina Kawaei also had to undergo surgery

AKB stands for Akihabara, the technology district of Tokyo, where the group has its own theatre. Members perform there almost every day.

Every year tens of thousands of fans vote on who gets to join the group from a pool of more than 200 candidates, in an event that is widely covered by national media.

Members have to abide by strict rules set by their management, and are not allowed to date.

When one of its members, Minami Minegishi, was caught spending the night with her boyfriend, she shaved her head in an act of contrition and apologised to fans in an online video.