The denuclearization of the Korean Peninsula will be the top issue as Chinese and US officials gather in Washington on Wednesday for the inaugural China-US Diplomatic and Security Dialogue (D&SD), according to a senior US diplomat.

US Secretary of State Rex Tillerson and Secretary of Defense Jim Mattis will host State Councilor Yang Jiechi and General Fang Fenghui, chief of the People's Liberation Army's Joint Staff Department, along with members of the US delegation and their Chinese colleagues for the D&SD.

The D&SD was established under the broader framework of the Comprehensive Dialogue mechanism that came out of US President Donald Trump's meeting with President Xi Jinping in April in Trump's Mar-a-Lago estate in Florida.

"We hope that the D&SD Dialogue - Diplomatic and Security Dialogue - will continue the positive momentum from that Mar-a-Lago meeting. And we think it will enable us to deepen our communication and make progress on priority issues," Susan Thornton, acting assistant secretary of state for East Asian and Pacific affairs, said on a conference call on Monday.

She expressed that the D&SD will more narrowly focus on key security issues than the more wide-ranging strategic dialogues in previous years.

"Specifically, we are going to give the DPRK - North Korea issue - top priority in our discussions, aiming to advance concrete cooperation with China towards a peaceful resolution of the nuclear and missile threat from North Korea," she said.

China has proposed a "dual suspension" approach to address the issue. That is for the Democratic People's Republic of Korea to suspend its nuclear and missile activities and for the US and Republic of Korea to suspend their large-scale military drills.

Foreign Ministry spokesman Lu Kang stressed last Thursday that China has been strictly implementing relevant resolutions adopted by the UN Security Council, including those related to the DPRK's nuclear and missile issues.

"However, I have also said before that we never recognize the so-called unilateral sanctions imposed outside the framework of the Security Council resolutions, since we believe it is not conducive to resolving the relevant issue," he said.

Thornton said the two sides will also talk about some other important strategic issues, such as the South China Sea and maritime issues, working to defeat ISIS and other risk-reduction efforts and military-to-military relations.

"We remain committed to a policy that aims to expand cooperation with China where it's possible and also to narrow our differences on key issues," she said.

The Chinese side has not yet held a similar briefing. Foreign Ministry spokeswoman Hua Chunying said on June 1 that China has indisputable sovereignty over the Nansha Islands and their adjacent waters.

"It is lawful, legitimate and reasonable for China to conduct peaceful construction and deploy necessary defense facilities on its own territory, which is to exercise the right of self-preservation and self-defense under international law and has nothing to do with militarization," she said.

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