China will work with Southeast Asian nations to make the South China Sea a sea of peace, friendship and cooperation, he added.
Xi said that for some time developments in the South China Sea have attracted extensive attention.
China “unswervingly safeguards its own sovereignty and relevant rights and interests in the South China Sea,” the president said.
Xi made the remarks when addressing the opening ceremony of the fifth foreign ministers’ meeting of the Conference on Interaction and Confidence-Building Measures in Asia.
Observers said Xi’s remarks come at a time when the US is worsening the situation in the South China Sea by boosting its military presence there, and after the US and the Philippines embarked on joint military drills recently.
Outlining his ideas to increase security in Asia as a whole, Xi said, “We welcome countries outside the region making a positive contribution to peace and stability here and working with Asian countries to promote the security, stability, development and prosperity of Asia.”
Su Xiaohui, a researcher of international strategies at the China Institute of International Studies, said Xi’s remarks on the South China Sea illustrate two of China’s key strategic goals — championing State sovereignty and safeguarding regional stability.
Xi is also sending a message that “China does not accept any attempt to ruin the big picture”, and such attempts include the international arbitration sought unilaterally by the Philippines against China, Su said.
The “countries outside the region” mentioned by Xi include the US, which is partly responsible for tension in the South China Sea, Su added.
Zhang Junshe, a senior researcher at the PLA Naval Military Studies Research Institute, said that the US has recently “grouped” with countries such as the Philippines to “muddy the waters” by staging joint military drills in the South China Sea.
“This is a root cause that prompts militarization of the South China Sea region and rising tension there,” Zhang said.
In Singapore on Thursday, China and countries in the Association of Southeast Asian Nations agreed to “properly control and manage differences”, according to a Foreign Ministry release.
This year marks the 25th anniversary of the launch of dialogue relations between China and ASEAN.
All parties agreed that China and ASEAN countries should use the anniversary as an opportunity to “strengthen strategic communication, deepen mutually beneficial cooperation, and properly control and manage differences”, the release said.