Mexico's central bank says it is investigating an apparent attempt to hack into the payment systems of at least three local financial institutions, but no funds were stolen.
Connections to the central bank's payment system at two banks and a brokerage were compromised, said Lorenza Martinez, head of the central bank's own payment system.
"At this time, both the institutions and ourselves are monitoring in a diagnostic way to identify what the problem was," Martinez told local radio.
She denied reports that the central bank's payment system itself had been breached.
"This has not happened," Martinez said, adding that the problem was detected in the internet application used by some institutions to connect to the central payment system.
She did not identify which institutions had been affected but said no money was missing or stolen.
Mexican bank Banorte on Friday said via Twitter that there was an "incident" affecting the bank's connection to the central bank's payment system.
On Monday, in a written response to queries from Reuters, Banorte said it had not been the target of a cyber attack. It offered no details, however, saying only that "some clients saw a delay in executing transactions" due to Friday's issue.
In January, hackers attempted to rob the government-run export bank Bancomext, but officials said they were unsuccessful.
(Reporting by Michael O'Boyle; Editing by Tom Brown)