Japanese police and customs officers have arrested two U.S. nationals on suspicion of smuggling 50,000 tablets of synthetic drugs to Japan from Canada via the U.S. military postal service.

Babe Cole, 25, and William Jenkins, 27, both residents of Yokohama, were arrested Thursday.

Cole is a civilian worker at the U.S. Navy's Yokosuka base in Kanagawa Prefecture. Jenkins was dismissed from the same job in June. Both had served in the U.S. Navy.

Kanagawa Prefectural Police quoted Cole as saying he had been asked to smuggle the drugs and was promised a reward. Jenkins has denied being involved, according to investigation sources.