A suspected security breach is being blamed for a rash of fraudulent withdrawals at automated teller machines and has prompted Citigroup to halt transactions on bank debit cards used in the U.K., Canada and Russia, according to The New York Times. The move by Citi follows similar actions by Bank of America, Wells Fargo and Washington Mutual, which recently announced that they will replace the cards in question with new ones. The latest fraud is part of larger-scale wave of identify theft, which The Times says started when payment processor CardSystem Solutions experienced such a breach that exposed the personal information of an estimated 40 million cardholders.