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Iran-U.S. Confrontation in the Persian Gulf: An International Law Perspective



(Photo by: IRIB) This frame grab from Tuesday, January 12, 2016 video by the Iranian state-run IRIB News Agency, shows detention of American Navy sailors by the Iranian Revolutionary Guards in the Persian Gulf.

On January 12, 2016, 10 U.S. sailors were detained and later released by Iran’s Navy in its territorial waters. The latest spat spat reminisces of December 2006, when three U.S. warships entered Iranian territorial waters, leading to escalating tensions between the two states. Back then, the U.S. claimed that the Iranians had threatened to destroy the U.S. warships, whereas Iran claimed that they only wanted to control the transit of warships. Can Iran’s past and present behavior in its territorial waters be considered justifiable or in accordance with international law?

According to article 17 of the 1982 United Nations Convention on the Law of the Sea “ships of all States, whether coastal or land-locked, enjoy the right of innocent passage through the territorial sea.” The right of innocent passage involves the passage of a foreign ship through the territorial waters of another state and the reconciliation of two opposing interests. International law has recognized the right of passage in order to protect the interests of foreign states and to ensure that maritime traffic will not harm the interests of the relevant coastal state.

However, it is not clear whether this right applies to warships—defined by the convention as ships belonging to the armed forces of a State bearing the external marks distinguishing such ships of its nationality, under the command of an officer duly commissioned by the government of the State […], and manned by a crew which is under regular armed forces discipline.” Thus, is the passage of warships through the territorial waters a right or if it is based on the tolerance of the coastal state?

No U.S.-Iran confrontations has escalated to a military clash between the two sides since 1979. However, such a clash has come close to taking place. Therefore, Iran has perceived the presence of the U.S. warships in Iranian territorial waters, in the Persian Gulf and the Gulf of Oman, as a threat to its national security.

According to Iran, U.S. warships threaten the country’s national security by transiting through its territorial waters. Because the U.S. has not ratified the 1982 Convention, the right of innocent passage is not a definitive solution for this issue. Therefore, according to article 21 of the Convention, Iran manages the passing of warships through its territorial waters with a “system of prior notification,” based on its own regulations. 

Along with an increasing number of the states that defend the previous system of prior notification or prior authorization conditions (1958-1982), Iran acts within the framework of the “Act on the Marine Areas of the Islamic Republic of Iran in the Persian Gulf and the Oman Sea (1993).” In accordance with 1993 Act, Iran applies the innocent passage of warships through its territorial waters only after prior authorization of or notification to Iran as the coastal state.

International law does not distinguish between “commercial ships” and “warships” in the  provisions pertaining to the right of innocent passage under “Rules Applicable to All Ships Section” in the 1982 Convention and the 1958 Conventions. On the contrary, it has been claimed that the right of innocent passage through the territorial waters has been also recognized for warships.

According to the 1982 Convention, “coastal States may, in the exercise of their sovereignty within their territorial sea, adopt laws and regulations for the prevention, reduction and control of marine pollution from foreign vessels, including vessels exercising the right of innocent passage. Such laws and regulations shall, in accordance with Part II, section 3, not hamper innocent passage of foreign vessels.” However, these laws and regulations will not include any provision that eliminates the right of innocent passage.

After signing the 1982 Convention, some states including Denmark, Egypt, Malta, Libya, Indonesia, India, South Korea and Croatia have demanded  “prior notification” of warships passing through their territorial waters. In addition, other states including Oman, China, Poland, Yemen, the Philippines, Pakistan, Iran, Albania and Algeria have adopted regulations on “prior authorization” of warships passing through.

In practice, most states demand the prior notification and authorization of warships. Today about 38 states apply the prior notification and authorization conditions for warships transiting through their territorial waters. Therefore, the right of innocent passage for warships has not been recognized as a customary rule.

Consequently, it can be argued that the detention of U.S. sailors by Iran’s Navy in its territorial waters—an act justified by Iran’s national security concerns—would be consistent with the international law of the sea, considering that Iran is not a contracting party to the 1982 Convention and 1958 Geneva Convention.



Saeed Bagheri

Dr. Bagheri is Assistant Professor of Public International Law at Akdeniz University, Turkey. He received an LL.B. Law from Tabriz Azad University, an LL.M Human Rights Law from Allameh Tabataba'i University Faculty of Law and Political Sciences and a Ph.D. in Public Law (International Law) from Ankara University. Bagheri joined the Department of International Law as a faculty member in August 2015. He teaches courses on International Law and International Humanitarian Law. His main research interests focus on internaional humanitarian law, armed conflicts, nuclear law, energy law and human rights law. He has published articles in the areas of international law as well as international armed conflicts, nuclear law and humanitarian law.