Official says much still unknown about hack of Mexico banks

The head of Mexico's central bank says there is still much authorities do not know about the apparent hack of a system used by banks to transfer money among themselves.

Alejandro Diaz de Leon said Wednesday the preliminary investigation is looking at about $15 million (300 million pesos) in suspicious transfers.

Diaz de Leon declines to name the institutions that were targeted, but says there were five, including three banks.

He says the cyberattack shows the sophistication and frequency of such attacks are increasing. In this case, it appears the hackers sent fake payment instructions into the system from nonexistent accounts.

De Leon says institutions' money was diverted, but not that of their depositors. The institutions are responsible for their cybersecurity in connecting to the central bank's system.