Logo: to the web site of the Swedish Defence University

Several incidents have occurred between 2023 and 2025 against undersea cables in the Baltic Sea, including gas pipelines, communication-, and energy cables. This study has selected three events: Balticconnector, BCS East-West Interlink/C-Lion1 and Eastlink 2 to investigate how authorities communicate the threat against Critical Undersea Infrastructure through Proxy Warfare. While previous research has classified the threat against Critical Undersea Infrastructure, CUI, as hybrid threats, this study aims to deepen the understanding of threats in the Baltic Sea against CUI.

The theory applied is A. Mumfords’ theory of Proxy Warfare. Mumford defines Proxy warfare as the indirect act of a third party in a conflict. The study investigates the problem of grey-zone activities and describes how the threat is communicated through a qualitative systematic analysis of carefully chosen analysis questions. The material is based on official statements of authorities and media articles in close relation to the chosen events. 

The study’s main findings are that authorities’ unanimity is that the threat against CUI depends on grey-zone activities, with deliberate attacks and complex provision of material and economic support. Furthermore, Proxies in the maritime domain differ from land-based use as the proxies most likely are used for individual events and isolated attacks.