The Dutch Ministry of Finance is investigating a cyberattack that compromised some of its internal systems, officials confirmed Monday.

The breach was first flagged last Thursday after a third party alerted the ministry to suspicious activity. Internal security teams subsequently identified unauthorized access to several systems used by a department within the ministry. Authorities said the affected systems were part of the ministry’s primary infrastructure but were quickly taken offline once the intrusion was detected.

The ministry said access to the compromised systems has since been blocked while investigators work to determine how the attackers entered the network and what information may have been exposed. The incident has disrupted the work of some employees, though officials did not specify how many staff members were affected.

Key government services tied to taxation and customs operations remain unaffected, according to the ministry. Officials also said services provided to citizens and businesses continue to operate normally.

Authorities have not yet determined whether the attackers obtained sensitive data or who might be responsible for the breach. No cybercrime group has claimed responsibility so far, and investigators have not publicly identified a possible motive.

The incident comes amid a string of cyberattacks affecting Dutch organizations. Last month, a breach at the Dutch Custodial Institutions Agency — the government body overseeing prisons and detention facilities — exposed employees’ personal data, including email addresses, phone numbers and security certificates.

In February, telecommunications provider Odido disclosed a separate cyberattack that resulted in the theft of personal information belonging to roughly 6.2 million customers. The compromised data included names, bank account numbers, addresses, phone numbers, email addresses and identification details such as passport and driver’s license numbers.