Relations between China and Vietnam have undergone a subtle change following a series of provocative activities by Hanoi to disturb the routine installation of a Chinese oil rig in the waters off China's Xisha Islands.

While the oil rig, or Haiyang Shiyou 981, owned by China National Offshore Oil Corporation, started operating in early May, China Maritime Safety Administration issued a notice, demanding vessels sailing by avoid crossing into the three-mile radius around the drilling site to ensure safety.

In disregard of the navigation notice, the Vietnamese authorities, however, dispatched a large number of vessels, including armed ones, near to the site, ramming China's civilian ships and disturbing the normal operation of the Chinese drilling platform. The Vietnamese authorities also filed a protest, accusing the drilling operation of falling within "disputed waters" and violating the United Nations Convention on the Law of the Sea and the Declaration on the Conduct of Parties in the South China Sea. Hanoi has made use of the supposed "collision incident" in the South China Sea, incited by the media, to describe itself a victim bullied by China.

The Chinese oil rig operates 17 miles away from Zhongjian Island, which belongs to China's Xisha Islands, but 150 miles away from Vietnam's coastline. It is self-evident that the site falls into China's offshore waters and that the abovementioned operation is completely within the range of China's sovereignty, sovereign rights and jurisdiction and has nothing to do with Vietnam.

The Xisha Islands are a part of China's inherent territory and the drilling of the Chinese enterprise in its offshore waters is completely an internal affair that should be free from any outside interference.

In the face of provocative activities from Vietnam, China had to reinforce security precautions on the site to ensure the normal drilling of its oil rig and the safety of operating equipment and staff. To maintain China's normal maritime operations and ensure the safety of its operating vessels, equipment, personnel and navigation, it is a just move for Chinese vessels to fend off bumping Vietnamese vessels.

China has kept the utmost restraint in the face of Vietnamese provocations to avoid the escalation of a tense situation. In response to provocations, China only used civilian vessels and chose a diplomatic channel for communications with the Vietnamese.

However, this restraint has failed to win respect in exchange. Vietnam increased the number of vessels at the scene and even mobilized some armed ships and frogmen. They even put up a lot of fishing nets and barricades in the relevant waters, seriously threatening the safety of China's vessels, drilling equipment and personnel, and seriously endangering navigation.

The provocative activities have not only seriously infringed upon China's sovereignty, sovereign rights and right of jurisdiction, but will also cause serious damage to Sino-Vietnamese relations that are otherwise on the track of enhancing strategically mutual trust and deepening mutually beneficial cooperation.

In June 2013, Vietnamese President Truong Tan Sang paid a visit to China and held talks with Chinese President Xi Jinping. Both leaders unanimously agreed that friendship between China and Vietnam is for the common good of both peoples and both countries should continue to be "good neighbors, good friends, good comrades and good partners" to each other.

With the joint efforts of both leaders, China and Vietnam have laid out an overall pattern of coordinately advancing maritime, land and financial cooperation, ushering in a new future of booming development of bilateral ties. The working group for joint maritime development established by two countries has held two rounds of consultations and achieved some positive progresses.

In this context, both countries should join hands to cherish and carry forward the hard-won positive momentum and in particular, remain vigilant against any alienation instigated by the US and Japan based on their strategic interests.

There is no doubt that Vietnam's latest provocative activities in the South China Sea have had an unfavorable influence on its otherwise good interaction with China.

In order to maintain healthy development of bilateral relations and the stability of the South China Sea, the Vietnamese authorities should return to reason as soon as possible, immediately stop all provocative activities and withdraw all of their vessels and personnel from the operating site of the Chinese oil rig.

The author is a research fellow with the China Institute of International Studies. opinion@globaltimes.com.cn