Editor's Note:

Tensions have been building up over the South China Sea issue recently. US reconnaissance plane flew over some of China's islands and reefs and US Secretary of Defense Ashton Carter called for China and other claimants to immediately halt construction in the region.

In the long speech Carter delivered during the 14th Shangri-La Dialogue (SLD) in Singapore Saturday, he once again asserted US' right of transit in the region. Very close attention has been paid to his speech. Several experts at the SLD offered their views.

You Ji, a professor of Department of Government and Public Administration, University of Macau

It's normal that all the delegates were worried.

Tensions over the South China Sea enveloped the region before the SLD. But Carter adopted a generally mild tone for his speech and used a normal expression for his criticism of China. It indicates a positive return by the US to the fundamentals of the SLD, which is designed to contribute to regional security and stability.

The US' provocative move to humiliate its rival last year violated the SLD basic principles and showed a lack of respect for all participant countries.

The US, often constrained by reality and its domestic politics, hasn't set a clear strategic position for China and mainly adopts hedging. Hence, it always sways between two extremes: containment and strategic partnership.

But the Sino-US relationship generally stays healthy, which conforms to US strategy and long-term interests.

The US is clearly aware that since the South China Sea issue doesn't touch upon Washington's core interests, it doesn't have the necessity to trigger an irreversible military confrontation with China, although the US needs to make commitments to its allies and partners in this regard.

Both Carter's harsh words ahead of the SLD and the milder tone stay with the US' basic principle of maintaining smooth relations with China.

In fact, the US must have taken into consideration that the coming US visit by Chinese President Xi Jinping in September would be affected if Carter strongly accused China in Singapore. The ambivalence also relates to what real actions the US will take in the South China Sea.

On the other hand, while repeatedly emphasizing peaceful resolution to disputes, Carter described the US military presence and capabilities in Asia to signal a warning with muscle flexing.

Jin Yinan, a professor of strategy, PLA National Defense University

Carter's remarks were generally comprehensive as he looked after the demands of all parties in his address, not just the US side. The security of the Strait of Malacca, which he mentioned that he watched on the flight into Singapore, has much more bearing on China than the US, and we are more concerned with freedom of navigation.

Carter should know China's historic rights and forbearance in the South China Sea. China started its construction in the area later than other claimants. Once the construction work finishes, China's facilities will undoubtedly make the greatest contribution to freedom of navigation and anti-piracy in the whole region.

Carter's remarks were full of delicate wording. However, some small countries want to drive a wedge between China and the US. They used the following Q&A session after his speech to make some gains. Carter responded in a somber way.

The US has drawn lessons from the provocation last year made by then Pentagon chief Chuck Hagel. The SLD shouldn't be turned into a platform of confrontation and criticism, causing rifts in Asia. After all, we attend the event to seek cooperation.