Beijing has been constructive in handling ties with Hanoi and Manila despite their recent maritime claims in South China Sea

The United States has termed the establishment of Sansha city in Hainan province by China to administer Nansha, Xisha and Zhongsha islands an "unhelpful" act. This unfair and unhelpful remark of the US is regrettable.

For ages, China has explored and tapped the entire aforementioned areas in the South China Sea and successive Chinese governments have ruled over various parts of the islands and waters for more than 10 centuries. It is on this basis that the Chinese government officially reiterated its sovereignty over the islands and waters, along with Dongsha Islands, in the 20th century.

This met with no international objection until a couple of decades ago. The Philippines had limited its westernmost territory east of Huangyan Island, the easternmost island of China's Zhongsha Islands. Till the 1970s, Hanoi agreed repeatedly and officially, in various written and verbal forms, with China on Chinese sovereignty over Nansha and Xisha islands.

It was only after the 1970s and after Vietnam was united that it started to negate its previous statements. Similarly, it was in the past decade that the Philippines started expanding its territorial claim to the Huangyan Island.

There may be disputes on sovereignty over the overlapping waters off the continental shelf between a country or countries ringing the South China Sea. However, there was no dispute between them and China over the islands and islets in the South China Sea until the 1970s.

If Vietnam and the Philippines are ambitious to expand their sovereign claim over Nansha, Xisha and/or Zhongsha islands, they have to talk with China. Taking unilateral action to make changes without seeking China's consent will simply not work.

China's decision to establish the city of Sansha is a response to the provocative actions of Vietnam and the Philippines, so that it can more effectively administer the areas and enforce China's legal jurisdiction over its sovereign space. This action is within China's sovereign rights and serves to deter predatory actions of some of China's neighbors, though it has come belatedly.

It is in this context that the US remark on Sansha should be seen. The US has called for regional stability. But it is the change in Vietnam's stance of recognizing China's sovereignty over Nansha and Xisha islands that has altered the status quo. Hanoi's move has destabilized the region and created tension in the South China Sea.

Similarly, the change in the Philippines' long-held position over the Huangyan Island, reinforced recently by its gunship threat to Chinese fishermen, has impaired China's sovereignty and hence destabilized the South China Sea.

One wonders why the US says China is "unhelpful" instead of saying that Vietnam and the Philippines have negated their long-held sovereign policy over parts of or the entire Nansha, Xisha and Zhongsha islands and islets.

It is true that China and the US, as well as all other countries, will benefit from regional stability. But the US' response to the provocative actions and change in positions of Vietnam and the Philippines should be impartial.

China is not demanding that Vietnam and the Philippines yield their legitimate national interests in the South China Sea; it is asking them to honor their past statements and documents which recognize China's sovereignty over the islands and islets. To unilaterally change a policy that affects two countries and use military means to enforce that change is irresponsible and unacceptable.

Contrary to the other countries' actions, China has exercised utmost restraint toward its neighbors despite their predatory moves. It is Beijing, not Hanoi and Manila, that has been constructive in handling its relations with neighbors over the disputes.

The US government has demanded freedom of navigation in international waters, including the South China Sea. In fact, Beijing and Washington have a common interest in ensuring that international waters are easily accessible for peaceful purposes.

However, the US' partial stance on the South China Sea - calling the responsible actor "unhelpful" and ignoring the provocative actions of the other countries - is creating regional instability in this part of the world. And it will be responsible for sowing the seeds of realpolitik.

The author is a professor of international relations at Fudan University, Shanghai.