European police have arrested 61 people accused of involvement in “skimming” bank and credit cards. The EU police organization Europol says the ring is believed to have stolen $70 million from accounts around the world during the past nine years.

Skimmers use an illegal electronic device to copy data from the magnetic strip of consumers’ payment cards. The information is then used to steal from the cardholders’ accounts.

In a joint operation last week by Europol, the U.S. Secret Service, and Bulgarian police , 47 suspects were detained in Bulgaria, nine in Italy, two each in Spain and the United States and one in Poland. The ring was linked to criminal cells in Kenya, South Africa and the United States.

Europol said more arrests are likely.

Most of the credit card information had been skimmed at automated teller machines in Europe.

Pressure is mounting in Europe for banks to issue cards with an electronic chip that cannot be copied, rather than cards with a magnetic strip.