China’s Ministry of Natural Resources released a report Monday, contending that US “freedom of navigation operations” (FON) in the South China Sea have “no legal basis” under international law. The report, authored by the China Institute for Marine Affairs, aims to provide a legal framework for Beijing’s long-standing opposition to US naval patrols.

China’s report argues that the program primarily serves “the national interests and geopolitical strategy of the US.” It contends that Washington has distorted the UN Convention on the Law of the Sea (UNCLOS) while refusing to ratify it, and that the US “selectively applies the provisions of the Convention in its favor,” undermining its integrity.

The report further evaluates US FON as marked by unlawfulness, unreasonableness, and double standards. It argues that the program distorts UNCLOS through unilateral interpretations, has shifted from protecting commerce to projecting military power, and allows the US to impose its views by force while avoiding treaty obligations—thereby weakening the international maritime legal order.

The US FON Program, launched in 1979, combines diplomatic protests and military operations to challenge what Washington deems excessive maritime claims. Through FON operations, US naval vessels and aircraft transit contested waters, including regular passages in the South China Sea, to reaffirm that coastal states cannot restrict navigation rights guaranteed under international law.

The US maintains that its operations in the South China Sea are lawful and intended to preserve access to key shipping lanes in the South China Sea, which carries nearly one-third of global maritime trade. In 2016, a tribunal constituted under UNCLOS rejected Beijing’s “nine-dash line” claims in the South China Sea. China dismissed the ruling and has since continued to assert jurisdiction over disputed areas.

China’s Ministry of Foreign Affairs has described US FON operations as provocations that undermine regional peace and stability. This new report formalizes that position in legal terms, concluding that the program “seriously distorts the interpretation and development of international law.”

The release of this report comes as US naval patrols intensify and China expands its presence through artificial islands, military facilities, and new legal claims, underscoring that the South China Sea has become not only a strategic flashpoint but also a battlefield for competing visions of international law.