Some 1,200 Tube travellers have had their online payment accounts hacked, according to Transport for London (TfL).
TfL said while no customer payment details had been breached it had “temporarily suspended” online contactless and Oyster accounts.
A Tfl spokesperson said: “As a precautionary measure and to protect our customers’ data, we have temporarily suspended online contactless and Oyster accounts while we put additional security measures in place.”
TfL said it believed hackers accessed the accounts of Oyster customers via a third party breach; people who might have recycled their passwords and logins for other websites.
“We encourage all customers not to use the same password for multiple sites,” said TfL.