Hackers gained access to some 14,000 credit card numbers in Chile and published them on social media, the government has said.
The government's bank regulatory agency said the hack was carried out by a mysterious group called the Shadow Brokers, known for hacking the NSA in the United States in 2016.
In this case the hackers published the credit card numbers, expiration dates and security codes. Banks scrambled to cancel the cards.
The banks affected by the attack included Santander, Itau, Scotiabank and Banco de Chile. They notified clients of the intrusion.
The government did not say what the potential financial loss was.
In June, Banco de Chile, one of the biggest in this country, said hackers robbed it of $10 million.
That hack was carried out from eastern Europe or Asia and some of the money ended up in Hong Kong, the bank said.