Hybrid Threats and the Law of the Sea

Use of Force and Discriminatory Navigational Restrictions in Straits


Read also Alexander Lott's blog on the recent Award of the Annex VII Arbitral Tribunal in the dispute concerning the Kerch Strait incident.

Hybrid Threats and the Law of the Sea debates the practice of states that have resorted to discriminatory navigational restrictions or aggression against foreign ships and aircraft in densely navigated straits. The book explores both widely acknowledged and lesser-known maritime incidents that meet the characteristics of hybrid warfare or hybrid conflict. This research approaches hybrid threats from the perspective of the interrelationship between navigational restrictions, law enforcement, armed attack, and the legal regime of straits. It provides guidance for determining whether the rules of armed conflict or law enforcement are applicable to various naval incidents.
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Alexander Lott, Ph.D. (2017), is Marie Curie fellow at the Norwegian Centre for the Law of the Sea, University of Tromsø and affiliated to the University of Tartu. He has published monographs and many articles on maritime law and security.


List of Illustrations

Abbreviations and Euphemisms

part 1
The Meaning of Straits and Hybrid Threats
1The Implications of Hybrid Threats to the Maritime Domain

2The Legal Concept and Classification of Straits
 2.1 The Legal Concept of a Strait

 2.2 The Legal Classification of Straits

 2.3 The Law of Naval Warfare in Straits and Its Relation to the Law of the Sea

3The Concept of Hybrid Threats
 3.1 The Meaning of Hybrid Conflicts

 3.2 Differences between the Rules on the Use of Force in Maritime Law Enforcement Operations and Armed Conflicts

 3.3 The Meaning of Hybrid Warfare

part 2
Use of Force in Maritime Hybrid Warfare
4Permit-Based Passage v. Transit Passage in an Occupied Area The 2018 Kerch Strait Incident and the 2022 Ukraine-Russia Naval Warfare
 4.1 The Kerch Strait Incident and Its Implications for the Passage Regime in the Sea of Azov

 4.2 Freedom of Navigation of Ukrainian and Russian Ships in the Kerch Strait

 4.3 A Critical Analysis of Ukraine’s Arguments about the Applicability of Transit Passage to Ships and Aircraft in/over the Sea of Azov and the Kerch Strait

 4.4 The Significance of 2003 Bilateral Treaties for the Passage Regime of the Kerch Strait

 4.5 The Sea of Azov as a Potential Historic Bay and Its Implications for the Regime of Passage in the Kerch Strait under Article 35(a) of losc

 4.6 The Importance of the Obligation of Non-recognition for the Passage Regime of the Kerch Strait

 4.7 Parallel Legal Regimes vs Sui Generis Regime of the Kerch Strait

 4.8 The Kerch Strait as a Belligerent Strait

5Use of Force against Sovereign Immune Vessels Law Enforcement v. Humanitarian Law Paradigm
 5.1 In dubio pro jus in bello?

 5.2 Threshold of an Armed Attack in a Hybrid Naval Conflict

 5.3 Distinction between Law Enforcement and Humanitarian Law Paradigms

6Iran-Israel ‘Shadow War’ in Waters around the Arabian Peninsula and Incidents near the Bab el-Mandeb
 6.1 Legal Regime of the Bab el-Mandeb

 6.2 Geopolitical Characteristics of the Bab el-Mandeb

 6.3 Terrorism and Piracy in and near the Bab el-Mandeb

 6.4 Armed Conflict in Yemen

 6.5 Background of the Iran-Israel Conflict

 6.6 Problems with Attributing State Responsibility

 6.7 Non-state Actors and Article 51 of the UN Charter

7Russia’s Military Operations in the Territories of the Viro Strait’s Coastal States
 7.1 Geographical and Geopolitical Characteristics of the Viro Strait

 7.2 The Legal Regime of the Viro Strait

 7.3 Foreign Military Activities in the Viro Strait: Incursions of Foreign Submarines and Military Aircraft

part 3
Discriminatory Navigational Restrictions in Hybrid Conflicts
8Discriminatory Prohibition of the Right of Transit Passage of a Commercial Ship The Arrest of Stena Impero by Iran
 8.1 Geographical and Geopolitical Characteristics of the Strait of Hormuz

 8.2 Legal Regime of the Strait of Hormuz

 8.3 The 2019 Stena Impero Incident and the Traffic Separation Scheme in the Strait of Hormuz

 8.4 Parallel Passage Regimes in the Strait of Hormuz?

 8.5 Significance of Iranian Internal Waters for the Passage Regime in the Strait of Hormuz

9Tensions in and over the Taiwan Strait in 2021
 9.1 Legal and Geographical Characteristics of the Taiwan Strait

 9.2 Navigation in the Taiwan Strait in the Light of Recent Developments in China’s Legislation

 9.3 Geopolitical Tensions in the Taiwan Strait and Intrusions of Taiwan’s Air Defence Identification Zone

10Discriminatory Navigational Restrictions in the Kerch Strait in Respect of Foreign Commercial Ships
 10.1 The Significance of the Kerch Strait for Commerce

 10.2 Restrictions on Foreign Commercial Ships’ Navigation through the Kerch Strait

11Discriminatory Prohibition of the Right of Innocent Passage of a Commercial Ship The Vironia Incident in the Gulf of Finland
 11.1 Right of Innocent Passage in the Eastern Gulf of Finland from 1920s to 2000

 11.2 The Russian Federation’s Maritime Zones in the Gulf of Finland

 11.3 The Vironia Incident in the Gulf of Finland and Its Aftermath

 11.4 Potential Legal Basis of the Russian Federation’s Permit-Based Passage Regime in the Gulf of Finland

part 4
Major Maritime Industrial Projects, Piracy, and Unidentified Soldiers
12The Nord Stream Project and Estonian-Russian Incidents in the Viro Strait
 12.1 Link between Industrial Projects and Maritime Security

 12.2 The Significance of the Viro Strait’s eez Corridor for the Nord Stream Project

 12.3 Marine Scientific Research in the Context of Seabed Studies on the Pipeline Route

 12.4 The Incident between the Estonian Coast Guard and Russian Research Vessels in the Viro Strait’s eez Corridor

 12.5 Permit-Based Marine Scientific Research in an eez: Estonia’s Decision to Deny Seabed Surveys

13Countering the Threat of ‘Little Green Men’ in the Åland Strait
 13.1 Geopolitical Characteristics of the Åland Strait and Preparations to Counter Unidentified Soldiers on the Åland Islands

 13.2 Legal Regime of the Åland Strait

14Threats of Piracy in the Straits of Malacca, Sunda, Lombok
 14.1 Legal and Geopolitical Characteristics

 14.2 Threats of Piracy in Indonesia and the Straits of Malacca and Singapore

part 5
Concluding Observations on the Implications of Hybrid Threats for Maritime Security Law
15A Need for a New Legal Framework on Hybrid Naval Warfare?

16Discriminatory Navigational Restrictions in the Context of Hybrid Conflicts

17Low-Intensity Use of Force (Hybrid Warfare) through the Prism of Law Enforcement and an Armed Attack

18Guidelines for Distinguishing between the Rules of Armed Conflict and Law Enforcement in Grey Zone Naval Incidents
 18.1 Use of Force by State Vessels against Attacks Launched from Commercial Ships

 18.2 Use of Force against a Commercial Ship in a Law Enforcement Operation

 18.3 State vs State Scenario


Chronological Table of International Instruments

Table of National Legislation

Chronological Table of Cases

Chronological List of Maps


Practitioners working at international, European and domestic institutions as well as scholars and students interested in the law of the sea, maritime security, international relations, history, and Russian studies.
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