A credit card scam centred around two petrol stations in East Sussex is being investigated after more than 560 people reported fraudulent bank activity.
Anyone who recognises these two men is asked to call Sussex Police
Police said the amount stolen could be as much as £2.5m. Illegally obtained details were used across 20 countries in cash withdrawals averaging £300.
Two garages in Eastbourne, and Sidley, near Bexhill, are assisting officers with their inquiries.
Two men have been arrested and released on police bail until January.
Police said one of the men, a Sri Lankan in his 30s, had been taken back into custody in connection with his immigration status.
The second man is in his 40s and from Eastbourne.
Four men believed to be linked to the investigation were arrested in Spain after withdrawing money from cash machines there in September.
Sussex Police have also released CCTV images of two suspects withdrawing cash in Eastbourne.
It is understood chip-and-pin handsets in the petrol stations were swapped for identical ones which actually stored card details.
The false machines were then removed and the data on them used to clone bank cards.
Police said the information had been sold around the world, enabling the withdrawal of money from Sussex bank accounts at cash machines as far afield as Canada, Argentina and Mauritius.
Det Sgt Dick Bollard said: "A reasonable estimate of how many accounts have been compromised would be 2,000 to 2,500."
Police believe more victims could come forward as people check their monthly bank statements in the coming weeks.
Det Sgt Bollard described it as a "very large and complex investigation" which was expected to take "a considerable amount of time to progress".
"The petrol stations are as much the victims as the banks and account holders in this type of fraud and staff have been extremely helpful with our inquiries," he said.