The European Central Bank (ECB) on Thursday said its website had been hacked and some email addresses and other contact information stolen, but insisted no market-sensitive data was compromised.

ECB said the hacked database serves parts of the ECB website that gather registrations for events such as ECB conferences and visits. Most of the data was encrypted, but parts of the database including email addresses, street addresses and phone numbers were not encrypted.

The database also contained encrypted data on downloads from the ECB website, but no internal systems or market sensitive data were compromised as the database was physically separated, the ECB announced.

The theft came to light after an anonymous email was sent to the ECB seeking financial compensation for the data.

The ECB is contacting people whose email addresses or other data might have been stolen. All passwords have been changed on the ECB system as a precaution.

German police have been informed and an investigation has started. ECB data security experts have also begun addressing the vulnerability.