A man in his 30s was fatally stabbed at a law firm office in Tokyo's busy Ikebukuro area on Tuesday and the suspected assailant has been arrested, police said.

An emergency call was made around 11:50 a.m. from the Adire law firm office in the Sunshine 60 building, reporting that a staff member had been stabbed. The victim was taken to hospital with no vital signs and later confirmed dead.

The male suspect, who is 50, works at the same firm as the victim. Both men were at work on Tuesday. He fled the scene but turned himself in at a nearby police box and was arrested on suspicion of attempted murder.

The suspect, who stabbed the victim several times including in the neck, was carrying a knife when he showed up at the police box, an investigative source said.