Just a month after President Xi Jinping concluded his first state visit to the United States, US guided-missile destroyer USS Lassen entered the waters around China's Zhubi Reef in the South China Sea on Oct 27 without the permission of the Chinese government.

But this should not come as a surprise because Washington had been urging Beijing to halt its reclamation projects in South China Sea. The two sides are yet to reach an agreement on the issue.

On the pretext of "freedom of navigation", USS Lassen's entry into the waters around Zhubi Reef was aimed at hindering China's reclamation projects and preventing its militarily from establishing its presence in the regional waters. The fact is that such "patrols" could sabotage navigation security, which is why China has lodged a protest with the US.

The bigger question seems to be whether China can lay claim to the territorial waters on the basis of its Zhubi Reef and Meiji Reef in the South China Sea. The former is a circular reef about 3.2 nautical miles (about 6 kilometers) in length and less than 2 nautical miles in breadth, covering an atoll of about 16.5 square kilometers. Its higher west end is about half meter above water at low tide but goes under at high tide. The Meiji Reef, however, basically remains above water.

These "rocks", according to Article 121 of the United Nations Convention on the Law of the Sea, are allowed to "own" territorial sea. Despite that, China has exercised the utmost restraint by referring to themas "near-shore waters" in a bid to avoid unnecessary misunderstandings, safeguard regional stability and guarantee freedom of navigation, especially in the waters near its Nansha Islands.

The US, however, deems the islets and reefs, including the Zhubi and Meiji reefs, as low-tide elevations, which can neither have territorial waters nor be used as the baseline for measuring the breadth of territorial sea, according to Article 7 of UNCLOS.

Believing that China's reclamation projects will lead to de facto "militarization" in the region, the Obama administration abandoned its neutral stance and sent its warship in the hope of securing, what it believes is, freedom of navigation and backing other countries' territorial claims, and to further marginalize China.

But without informing the Chinese government in advance of its warship's entry into the waters around the Zhubi Reef, the US has violated Article 2 of the UN Charter that requires the principles for peaceful settlement of disputes without the threat or use of force, China's domestic laws and the mutual notification mechanism for major military activities that the two countries' defense authorities agreed to last year. Such actions will only escalate the tensions in the South China Sea, hampering China-US interaction and the efforts to resolve regional disputes.

There are certain things that Beijing can do should Washington keep its warships near the Nansha Islands. Apart from lodging protests with the US government, it can also assign its maritime forces to supervise and follow the "innocent passage" US warships and urge them to leave. Of course, China should earmark a "safe zone" to limit, even halt, the "innocent passage" of foreign, including US warships, when its security is under threat.

Also, it should publicize the baselines of some Nansha islets and reefs in accordance with the unfolding security situation, enhance management of the territorial sea, and take measures to steadfastly protect its legal interests.

Unlike what the US speculates, China's reclamation projects in the South China Sea can help provide better maritime services to the international community. Dissenting countries, such as the US, are supposed to engage in sincere dialogues with China, instead of resorting to military measures. As for Beijing, it should keep building public facilities and defense forces on the Nansha Islands along with strengthening its laws to reduce the gray areas of maritime management.

The author is director of the Ocean Strategy Studies Center at the Shanghai Academy of Social Sciences.