By David Dolan

TOKYO (Reuters) - A man who said he was tired of life went on a stabbing rampage on Sunday in a crowded Tokyo shopping street, killing seven people and wounding a dozen others.

The man drove a rental truck into a crowd of pedestrians at lunchtime and then walked down the street knifing passers-by in Akihabara district, known for its discount electronics and maid cafes.

"I came to Akihabara to kill people," Kyodo news agency quoted the attacker as telling police. "I am tired of the world. Anyone was OK. I came alone."

A Tokyo police spokesman said at least seven people had been killed and 12 wounded.

"The man jumped on top of a man he had hit with his vehicle and stabbed him with a knife many times," Kyodo quoted a 19-year-old witness as saying. "Walking toward Akihabara Station, he slashed nearby people at random."

The dead were six men aged 19 to 74 and a 21-year-old woman, the news agency said.

The police said a man had been arrested, and television stations showed a slight, blood-splattered 25-year-old being herded into a police car.

Witnesses said the rampage was stopped when a policeman armed with a gun confronted the man, who NHK television said was shouting as he cut down his victims.

The street, usually crowded with tourists and locals seeking cheap gadgets, was cleared by police, who searched for evidence amid pools of blood.

"It's pretty shocking, considering that I come here all the time," a man told NHK.

The rampage came on the seventh anniversary of a massacre at a Japanese primary school, when a knife-wielding janitor and former mental patient killed eight schoolchildren. He was later executed for the killings.

Although Japan has relatively little violent crime, such high-profile cases have raised public concern about violence.

Shooting deaths remain rare in Japan, although there have been some recent cases involving "yakuza" criminal gangs.

As well as electronics, Akihabara has become known in recent years as a centre for Japan's expansive "nerd" culture of video games, comic books and outlandish fashion -- including street performers and cafes with waitresses dressed as French maids.

(Editing by David Fogarty)