Mexico's attorney general's office is investigating an attempt to hack and rob Bancomext, the government-run export bank, an official told Reuters on Thursday.
The hackers were not successful in siphoning money from the bank's accounts, said the official at the attorney general's office, who declined to be named. He said some funds had been frozen but he did not specify the amount.
"Emergency protocols were activated immediately, a malfunction was detected and the money was protected," he said.
On Tuesday, Bancomext alerted clients that it had suspended operations and by Wednesday the bank said it had been hacked in a method similar to other attacks around Latin America.
"Fortunately, the protocol and quick reaction of the area responsible for operation, with the help of banks, corresponding authorities and the Bank of Mexico, contained this incident," Bancomext said in a statement.
A spokesman from Bancomext did not immediately reply to a request by Reuters for further comment.
SWIFT, the global messaging system used to move trillions of dollars each day, has been used by hackers to attack banks around the world, but the Brussels-based company has declined to disclose the number of attacks.
The central bank of Bangladesh lost US$81million in one such cyber heist in February 2016 and there were reports of attacks late last year in Taiwan and Russia.
Cyber thieves stole US$12million from an Ecuadorian bank in 2015, allegedly using SWIFT to move the funds.
It was not clear if the Mexico attack utilized Bancomext's SWIFT system. SWIFT spokesman Natasha de Teran declined to comment.