Tesco Bank customers will not be able to complete online transactions throughout Monday after a hacking attack.

The bank's chief executive Benny Higgins said the move was an emergency security measure.

Mr Higgins did not say if the online transactions freeze would last beyond Monday.

Some current accounts were subjected to "online criminal activity" over the weekend, with "some cases" resulting in money being withdrawn fraudulently, he said.

Mr Higgins said customers affected by the block will still be able to withdraw cash and use other services.

He also sought to reassure customers that Tesco Bank will "ensure they do not lose out financially" and accounts will be refunded "as soon as possible".

The Financial Conduct Authority says banks must refund unauthorised payments immediately, unless they have evidence that the customer was at fault or the payment was more than 13 months ago.

The bank, which has 7.8 million customer accounts, is working with authorities and regulators to address the circumstances surrounding the security breach.