An official with the Industrial and Commercial Bank of China (ICBC) on Thursday called on the bank's online banking customers to guard their personal account information after a series of online thefts across 20 provinces were reported.

The official told Xinhua in an exclusive interview: "No hacker has managed to access ICBC's online banking system. Based on results from police investigations, the online deposit stealing cases occurred mainly due to the unexpected divulging of customer's personal information."

ICBC currently has 20 million online banking customers.

The bank has taken new measures to prevent online theft, such as updating firewalls, adopting encrypted information transfer and launching real-time scanning, the official said.

"However, some customers' awareness of preventing stealing is too weak," he said, citing a recent example in which a company's senior manager entrusted a member of his staff with his bank card and pin number. The staff member then used the bank card and pin to apply for online banking and stole a huge sum from his manager's bank deposits.