Police were called to a restaurant in a Tokyo skyscraper Sunday after a mass brawl erupted among around 100 customers who appeared to be members of a group with links to organized crime.

Most diners had already left the function that had booked out the whole restaurant when officers reached the modern French eatery on the 58th floor of the landmark Sunshine 60 tower in the Ikebukuro district, with only a man who had suffered a minor head injury and a handful of others remaining, the police said.

File photo taken from a Kyodo News helicopter in June 2012 shows the Sunshine 60 tower in Tokyo’s Ikebukuro district. (Kyodo)

According to an investigative source, those involved in the commotion appeared to be members of Chinese Dragon, a gang comprised primarily of second- and third-generation descendants of Japanese orphans left behind in China when Japan withdrew from the country at the end of World War II.

Police have received information that the function was intended to celebrate a member’s release from prison. The scene was littered with broken beer bottles and glasses, the police said, adding they are investigating the incident as a suspected case of property damage.

A restaurant clerk made an emergency call around 6:30 p.m. after the group started eating and drinking at about 6:00 p.m. and suddenly got into a fight, they said. There were no customers other than the dining party.

No staff were injured and the man found at the scene with the head injury was transported to a hospital, police said.