The heist saw the thieves deploy pepper spray to grab luggage containing the money at around 9:30 pm (1230 GMT) Thursday near Ueno station, an area popular with tourists, a spokeswoman at the Tokyo Metropolitan Police told AFP on condition of anonymity.
She declined to give further details of the case, but local media said the victims were a group of five Chinese and Japanese nationals who were trying to place suitcases containing some 420 million yen ($2.7 million) in a vehicle. It was not immediately clear why the group was carrying the money.
Fuji Television said the victims told investigators that the cash was being delivered to currency exchange stations. Separately, a man with 190 million yen in cash was also attacked with pepper spray by a group of three men in the early hours of Friday morning at a parking garage at Tokyo’s Haneda airport, local media said. Police were investigating the link between the two attacks, broadcaster TBS said.