The Kushiro customs office seized on Monday about 10 kg of cocaine at Tokachi port in southern Hokkaido, but the man who had been carrying the haul fled the scene, police said Tuesday.

The man, whom police said appeared not to be Japanese, dropped a knapsack containing the drugs and fled around 6:40 p.m. when an official of the customs office's Tokachi branch started questioning him.

According to police, it is the largest cocaine haul this year with a street value of about 600 million yen. The narcotic was wrapped in 10 bags, each weighing 1 kg, they said.

Authorities said they searched a Filipino-registered cargo vessel anchored nearby on suspicion it was involved.

According to investigations, the ship left Chile on July 6 and arrived at Tokachi port Friday via Kushiro port.

The Kushiro customs office received a tip that drugs were on board the vessel shortly before it arrived in Hokkaido, authorities said.