Cyber thieves hacked into a database at European Central Bank (ECB) and stole email addresses and contact information for users who signed up for bank events via its public website, ECB said Thursday.

The bank discovered the breach after attackers sent an anonymous email requesting money in exchange for the information. 

While most of the data was encrypted, “parts of the database included email addresses, some street addresses and phone numbers “ were not,  ECB said in a press release. “The database also contains data on downloads from the ECB website in encrypted form.”

Saying that it was contacting potential victims and that all passwords have been changed, the bank said the database is “physically separate” from its internal systems, none of which had been compromised. The bank also informed German police, who, subsequently, are conducting an investigation.