British cell phone retailer Carphone Warehouse says personal details of up to 2.4 million customers may have been accessed after the company was hit by a cyber-attack.

The company said the security breach, discovered Wednesday, could have included names, addresses, dates of birth and bank details.

It said Saturday that up to 90,000 customers may also have had their encrypted credit card information accessed.

Sebastian James, group chief executive of Dixons Carphone, said the company was informing anyone who may have been affected. The company said it has launched an investigation and has also implemented new security measures to prevent further breaches.

Dixons Carphone operates in about a dozen European countries including Britain, Ireland and Germany.