Chaos broke out after the attacks at the crowded mall, with the sirens of several ambulances blasting through the compound and people frightened by the sight of bleeding victims trying to escape, Japanese media reported.

The incident occurred in the city of Tsuchiura, said Mr Kiyoto Ogata, a police spokesman. At least seven shoppers were injured and an eighth - a 27-year-old man - died as he was rushed to a nearby hospital, he said.

Police arrested the alleged attacker, a 24-year-old jobless man Masahiro Kanagawa who was wanted over the earlier slaying of a 72-year-old man, Mr Ogata said.

The extent of the victims' wounds and the attacker's motive were not immediately known, he said.

Violent crimes are relatively rare in Japan, where most shootings and stabbings are committed by the nation's 'yakuza' crime syndicates. Authorities have been concerned about a recent rise in street violence, however.

In December, a man gunned down two people in a southern Japan sports club before killing himself. -- AP