Underwater Defense: NATO Makes the Mediterranean a Frontier against Hybrid Threats

NATO is significantly intensifying its efforts to safeguard Critical Underwater Infrastructure (CUI) in the Mediterranean region, emphasizing the need for a unified civil-military response against the escalation of hybrid threats.

The Critical Underwater Infrastructure (CUI)-Network of the Alliance met in Rome, Italy, on November 20-21, 2025, involving experts from NATO Headquarters, Allied Countries, industrial stakeholders, European Union representatives, and, for the first time, NATO partner countries.

Expansion of Cooperation and Surveillance

The focus of the meeting was the integration of perspectives and best practices for securing vital underwater systems — such as pipelines and communication cables — in the Mediterranean and beyond, a region considered "critical" for the Alliance's 360-degree security approach.

A key theme was the deployment of detection and surveillance technologies, including drones, to enhance security around this expanding and increasingly vital infrastructure.

Participants gained firsthand insight into joint civil-military efforts during a visit to the Italian Navy's Critical Underwater Infrastructure Surveillance Center. The center demonstrates how stakeholders monitor and coordinate rapid responses to suspicious activities near the CUI.

"A 360-degree approach to security is vital for the Alliance. The Mediterranean region could not be more crucial," stated Ambassador Jean-Charles Ellermann-Kingombe, NATO Deputy Assistant Secretary General for Cyber and Digital Transformation and Special Coordinator for Hybrid Threats.

"We are here to deepen our exchanges and expand the scope of our cooperation between the civil, military, public, and private sectors," he added, noting the interconnected nature of threats and challenges.

Post-Baltic Security Boost

NATO's CUI-Network was established in February 2024 with the aim of improving information sharing and coordination on infrastructure resilience.

The increased focus on CUI follows disruptions to underwater infrastructure in the Baltic Sea in December 2024, which prompted NATO to launch "Baltic Sentry". This multi-domain activity aims to strengthen NATO's military presence and enhance Allies' ability to respond to destabilizing acts.

The Rome meeting marks a geographical expansion of this urgent security priority, solidifying the Mediterranean's place at the forefront of NATO's strategy to deter and defend against hybrid threats directed at essential infrastructure.