Tesco Bank (LON:TSCO) of Edinburgh, United Kingdom, has stopped all online transactions after reports that money has been stolen from 20,000 accounts of customers, making this a major online fraud in the country. The hacking incident happened over the weekend with what is the banking division of the largest supermarket chain in the UK.

There are about 40,000 accounts with Tesco. So the incident happened with about half of the accounts. But there were suspicious activities in the other 20,000 accounts as well, but as of now, they are safe.

Tesco has about 8 million customers and £8.1 billion or $10 billion in deposits.

Customers Unable To Reach Tesco Bank

The amount stolen has not been disclosed. However, customers at online support forums are reporting that “several thousands of pounds” have gone from their checking or current accounts. Some customers are complaining over social media that Tesco is not answering phones. Others are saying that they could only reach the bank after calling repeatedly for several hours. One more person said he was put on hold for 45 minutes before someone from the bank took the call.

The bank has assured them saying that the money will be refunded to the accounts within 24 hours.

In the meantime, Tesco has stalled all online transactions as a precautionary measure. Chief Executive of Tesco (LON:TSCO) Benny Higgins said we are stopping all online transactions to protect our customers. Such things should not happen. Benny assures Tesco customers they can still use their cards for withdrawing money from ATM machines and use them in shops. The situation is under control now, he says.

Tesco Bank Growing Quickly

Tesco has grown quickly in their effort to grab market share from the four big banks in the UK – Barclays, HSBC, RBS, and Lloyds. Tesco Bank has been offering 3 percent interest to their customers for balances up to £3,000, whereas competitors such as Santander, for example, are reducing the rates for current accounts.

But this latest fraud incident is sure to be a dampener. Many customers are likely to question the safety of the bank’s systems.

The bank has issued no explanation on how the fraud happened or who was responsible for this. Benny Higgins just said, “We continue to work with the authorities and regulators to address the fraud and will keep our customers informed through regular updates on our website, Twitter and direct communication”.