In its 2017 Report on the Freedom of Navigation, the United States Department of Defence (DoD) criticised Malaysia and 21 other countries for making excessive maritime claims. The United States. maintains that Malaysia has undermined the freedom of navigation and contravened customary international law.

DoD has faulted Malaysia on two grounds: requiring prior notification for nuclear-powered vessels to enter their territorial sea, and failing to authorize foreign powers to conduct military exercises in its exclusive economic zone (EEZ). Other states requiring prior notification for foreign warships to access their territorial seas include Albania, China, Croatia, India, Maldives, Malta, Oman, Pakistan, South Korea, Thailand and Vietnam.

The origin of Malaysia’s restrictions on nuclear-powered ships and military maneuvers can be traced to a declaration it deposited with the United Nations on the 14th of September, 1996. Consistent with the Vienna Convention on the Law of Treaties of 1969, the declaration reads that Malaysia “understands [that] the provisions of the Convention do not authorise other States to carry out military exercises or manoeuvres, in particular those involving the use of weapons or explosives in the exclusive economic zone without the consent of the coastal State”.

It is worth noting that the concept of EEZs is found only in UNCLOS, of which the U.S. is a signatory, but has yet to ratify. The U.S. insist that the “international uses” described in Article 87 of UNCLOS include the right to conduct military maneuvers in EEZs. However, the 27 states that have ratified UNCLOS disagree with the U.S. and do not adhere to this interpretation.

These countries point to the absence of specific provisions in UNCLOS permitting foreign countries to conduct military activities in EEZs. Separately, they take the view that phrases in UNCLOS which refer to the “rules of international law” in Article 87 (1), and of “internationally lawful uses of the sea” in Article 58 (1), do not apply to military exercises.

As such, Malaysia’s official policy is that as long as maritime activities are military in nature, they are prohibited in the Malaysian EEZ, without its expressed consent. Unauthorised military activities are considered a threat to the security Malaysia.

The 1996 declaration also stipulates prior authorisation for the passage of nuclear powered vessels and vessels carrying nuclear materials in its territorial sea. This restriction is primarily targeted at vessels transiting through the accident-prone and traffic-congested Strait of Malacca.

Malaysia contests the unauthorised right of foreign countries to conduct military exercises in its EEZ on the ground of sovereignty, law and security. In Malaysia’s view, as a coastal state, subject to legally accepted constraints, Malaysia has absolute sovereign jurisdiction in its territorial sea and EEZ.

There is no international law that explicitly prohibits Malaysia from claiming jurisdiction over foreign military activities in its EEZ. Unauthorised foreign military activities can undermine and subvert Malaysia’s security, and they can be non-peaceful in nature.

Malaysia views UNCLOS as a treaty that is only applicable to state parties. Although the treaty has come into force, not all the provisions have the force of opinio juris as customary international law, whereby states are obliged to obey, prescribe and enforce. The provision dealing with military activities at sea is one of them.

B.A. Hamzah is a lecturer with the Department of Strategic Studies, National Defence University Malaysia, Kuala Lumpur. He is also an Adjunct Research Professor, National Institute of South China Sea Studies, Haikou, China. This commentary first appeared at the New Straits Times.