Police seized a 1-ton cache of stimulants, the largest-ever haul in Japan, from a boat along the shore of the Izu Peninsula, a popular resort area southwest of Tokyo.

Tokyo's Metropolitan Police Department said June 5 that seven Chinese nationals were arrested on suspicion of possessing the stimulants in Minami-Izu, Shizuoka Prefecture.

The stimulants have a street value of about 60 billion yen ($555 million), police said.

Police are investigating possible links to an international smuggling group.

When officers arrived at the scene on the evening of June 3, the seven men attempted to flee but were captured.

A subsequent search of the boat turned up the drugs.

Officers of the MPD's organized crime division said the suspects were aged between 24 and 40, all unemployed with no fixed address.

The suspects denied the allegations, according to police.

The previous record was about 600 kilograms of stimulants found on a yacht anchored at Naha Port in Okinawa Prefecture in 2016.