BEIJING - China's sovereignty over Nanhai Zhudao, known in English as the South China Sea islands, rests on solid legal foundations, including the principles of discovery and occupation, effective jurisdiction, estoppel, and other relevant international law principles governing territorial acquisition, according to a think tank report issued Thursday.

The report, titled "Historical and Legal Basis of China's Territorial Sovereignty and Maritime Rights in the South China Sea," was released by Xinhua Institute, a think tank affiliated with Xinhua News Agency.

China's earliest discovery and development of Nanhai Zhudao conform to the international law principle of "acquiring territorial sovereignty through discovery and occupation," according to the report.

READ MORE: China reiterates sovereignty over South China Sea islands

China's sovereignty claims over Nanhai Zhudao have received broad international recognition, conforming to the international law principle of "estoppel," it adds.

The Philippines and other regional countries' occupation of South China Sea islands and reefs based on the so-called "geographic proximity" violates relevant international law principles, according to the report.

China's claims to maritime rights and interests in the South China Sea conform to the international law principle of "land dominates sea" and China's historical rights in the South China Sea are protected by international law, the report notes.

This report is part of a series of three reports on the South China Sea issue released by Xinhua Institute. The other two are titled "Incitement, Threats, and Lies -- The Truth about External Forces Interfering in the South China Sea Issue," and "Making the South China Sea a Sea of Peace, Friendship, and Cooperation: China's Actions."

READ MORE: Philippines urged not to disrupt peace in South China Sea

Some external powers, through alliance-building and meddling in regional disputes, aim to maintain privileged position in the South China Sea and preserve maritime control for self-serving interests, according to a think tank report issued early this June.

Noting that the South China Sea is a crucial international maritime corridor, the report highlights that the freedom of navigation and overflight in this region, as guaranteed under international law, stands as a fundamental consensus between China and other coastal states.

However, some countries' growing interference through military and diplomatic channels undermines regional stability, it says, stressing that China consistently advocates for resolving differences through bilateral friendly consultations with relevant countries.