SINGAPORE — United States Secretary of Defense James Mattis has said China’s deployment of military assets to the disputed islands and features in the South China is for “intimidation and coercion,” saying the decision to uninvite China’s navy from participation in a multinational naval exercise is a direct response to these actions.

Speaking at the annual Shangri-La Dialogue in Singapore, which brings together defense ministers, military personnel and security experts to discuss regional security, Mattis also said these deployments are in direct contradiction to president Xi Jinping’s 2015 reassurances that China will not to militarize the South China Sea.

These included the recent placement of electronic warfare equipment to jam the aircraft and ships of potential adversaries, ground-based surface-to-air and anti-ship missiles on the artificial islands China has constructed in the South China Sea whose ownership is being disputed by five other regional countries, as well the recent landing of nuclear-capable H-6K bombers to another Chinese-held island in the strategic waterway.

Mattis confirmed again that the recent decision to withdraw the invitation to China’s People’s Liberation Army — Navy to participate at the upcoming Rim of the Pacific, or RIMPAC exercise to take place off Hawaii in June is a direction consequence of these Chinese deployments to the South China Sea. The decision was made even as Mattis called China’s involvement a means to display a cooperative stance and keep open the lines of communication between both countries.

In his speech, Mattis also touched on the recent renaming of the U.S. Pacific Command to Indo-Pacific Command, saying that the new name properly defines its area of responsibility, also referring to it as the “priority theater” for the U.S. military which will see the region get the U.S. Navy’s most capable ships along with 5th-generation fighter aircraft replacing older aircraft in the theater.

Unusually, the U.S. defense secretary also mentioned thorny issue of Taiwan in his speech, committing to “working with Taiwan to provide the defense articles and services necessary to maintain sufficient self-defense” for the self-governing island consistent with the obligations set out in the Taiwan Relations Act.

He also reiterated the U.S. opposition to any unilateral efforts to alter the status quo over Taiwan, insisting that any resolution of the Taiwan issue must be in line with the wishes of the people on both sides. China views Taiwan as a rogue province and has pledged to re-incorporate the island into the mainland by any means necessary, including the use of force. Arms sales to Taiwan generally draw loud protests from China, who has used its economic leverage to pressure countries into denying such sales.

However, Mattis also struck a conciliatory note in his speech, stating that China should and does have a voice in shaping the international system, and that the U.S. will continue to pursue a constructive results-oriented relationship with China, cooperation whenever possible.

The U.S. will also continue to stay engaged in the region, continuing a policy of security cooperation to bring its current “crucial” alliances with Korea and Japan to meet current security challenges, as well as enhancing the capabilities of partner nations and improving interoperability in both “hardware and software” by promoting the financing and sales of defense equipment to security partners and availing U.S. professional military education to more military personnel from Indo-Pacific countries.

Mike Yeo is the Asia correspondent for Defense News.

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