Mutual assistance

ENISA is supporting the EU Member States since 2012 to develop, implement and evaluate their National Cyber Security Strategies (NCSS). Since 2017, all EU Member States have published their own NCSS.

Mutual assistance

Member States shall establish mutual assistance processes. When an entity operates in multiple Member States or has systems located in different Member States, the authorities involved must cooperate and assist each other as needed. This includes informing and consulting each other about any supervisory or enforcement actions taken, one authority can request another to take specific supervisory or enforcement actions, authorities must assist each other by providing support proportionate to their resources to ensure effective and consistent measures.
The assistance can include information sharing, inspections, or audits. Authorities may refuse assistance only if they lack competence, if the request is disproportionate, or if it threatens national security or public safety. Before refusing, they must consult with other authorities, and, if needed, with the Commission and ENISA. Member States may also carry out joint supervisory actions by mutual agreement.

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Austria
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Belgium
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Bulgaria
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Croatia
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Cyprus
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Czech Republic
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Denmark
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Estonia
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Finland
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France
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Germany
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Greece
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Hungary
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Iceland
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Ireland
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Italy
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Latvia
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Liechtenstein
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Lithuania
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Luxembourg
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Malta
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Netherlands
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Norway
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Poland
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Portugal
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Romania
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Slovakia
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Slovenia
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Spain
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Sweden
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Switzerland
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Croatia

Operational cyber mutual assistance under the Cybersecurity Act: Croatia's operational cross-border mutual-assistance mechanism, transposing NIS2 Art. 37. Where an entity operates or has systems in more than one Member State, NCSC-HR - as Croatia's designated single point of contact - informs, consults and assists the competent authorities of other Member States on supervisory/enforcement measures, may request another authority to act, and provides mutual assistance (information requests, on-site inspections, joint supervisory actions). NCSC-HR is the operational channel to the EU CSIRTs Network, EU-CyCLONe and the NIS Cooperation Group. 

Sources: https://ncsc.hr/en 
https://ncsc.hr/ 

Denmark flag
Denmark

CSIRT International Cooperation through the Danish Defence Intelligence Service: Denmark’s national CSIRT and Government CERT is placed in the Danish Defence Intelligence Service (DDIS). It provides warnings, threat information, incident handling support and cybersecurity services to government entities and operators of critical infrastructure, strengthening national incident preparedness and response capabilities.

Sources: https://tf-csirt.org/trusted-introducer/directory/teams/cfcs/
https://www.fe-ddis.dk/da/arbejdsomrade-a/Cybertruslen/

NOST — National Operational Staff: NOST is Denmark's highest operational crisis coordination forum. NOST is activated when Denmark is affected by incidents requiring cross-sector coordination, including extreme weather, pro longed power outages, serious accidents, cyber incidents or attacks on critical infrastructure.

Sources: https://samsik.dk/krisestyring/nost/
https://politi.dk/om-politiet/samarbejde/den-nationale-operative-stab-nost

New joint 24/7 situation centre: The Danish Government announced the establishment of a 24/7 situation centre linked to NOST, alongside a national cyber operations centre and cyber monitoring network. These measures aim to strengthen detection, coordination, response and crisis management for cyber and hybrid threats.

Sources: https://mssb.dk/nyheder/nyhedsarkiv/2025/december/regeringen-nyt-faelles-247-situationscenter-i-lyset-af-hybridkrig/
https://mssb.dk/media/ywqbp0rh/baggrundsnotat.pdf

Hungary flag
Hungary

Operational cyber mutual assistance: Hungary's operational cross-border mutual-assistance mechanism, transposing NIS2 Art. 37 into the Cybersecurity Act (Act LXIX of 2024). Where an entity operates or has systems in more than one Member State, , the National Cyber Security Centre of Hungary (NCSC HU), informs, consults and assists the competent authorities of other Member States on supervisory/enforcement measures, may request another authority to act, and provides mutual assistance (information requests, on-site inspections, joint supervisory actions). NCSC HU is the operational channel to the EU CSIRTs Network, EU-CyCLONe and the NIS Cooperation Group.

Sources: https://nki.gov.hu/intezet/nemzetkozi-kapcsolatok-egyuttmukodes/
https://en.nki.gov.hu/
https://njt.jog.gov.hu/jogszabaly/en/2024-69-00-00

National Cyber Security Centre (NCSC-HU)National Cyber Security Centre of Hungary (NCSC HU) serves as Hungary's responsible CSIRT for sectors covered by the NIS framework. The Centre supports cybersecurity cooperation, provides assistance during cyber incidents, and serves as a key coordination point for cybersecurity activities at national and international levels.

Source: https://en.nki.gov.hu/

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Netherlands

Cross-border mutual assistance through the EU CSIRTs Network: NCSC-NL can request and provide operational assistance through the EU CSIRTs Network when incidents have cross-border effects. Assistance may include technical information, coordination and support from peer national CSIRTs. Dutch responders get a route to European help when an incident crosses borders. 

Source: https://www.ncsc.nl/over-ons/versterkt-ncsc 

Domestic detection assistance through the National Detection Network: Participants in the National Detection Network share technical information that can help other members identify and contain related threats. NCSC-NL coordinates the exchange and can turn individual findings into wider national awareness. The assistance is indirect but useful: one participant's detection can become another participant's early warning. 

Source: https://www.ncsc.nl/over-ons/versterkt-ncsc 

Sectoral CSIRT mutual support: Sectoral CSIRTs such as Z-CERT provide specialist support within their own communities and coordinate with NCSC-NL when an incident requires national or cross-sector assistance. The sectoral team contributes detailed operational knowledge, while NCSC-NL supports escalation and wider coordination. The model keeps specialist sector knowledge close to incidents while preserving a path to national escalation. 

Source: https://z-cert.nl/