The industry ministry has told the operator of Seven-Eleven convenience stores that its mobile payment service is not secure enough after customers were allegedly defrauded through unauthorized access and urged the company to submit preventive measures.

One of two Chinese men arrested on suspicion of attempted fraud paid ¥730,000 ($6,750) to buy 146 cartons of electronic cigarette cartridges at a Seven-Eleven outlet in Tokyo using stolen IDs for the new smartphone payment service 7pay, police said Friday.

The Ministry of Economy, Trade and Industry has determined the operator, Seven & I Holdings Co., failed to strictly follow guidelines to prevent unauthorized access and warned providers of similar services to ensure they confirm the identity of users.