WASHINGTON -- The United States is committed to ensuring a "free and open" Indo-Pacific region amid challenges posed by China, Defense Secretary Mark Esper said Monday, including South Korea among his country's partners.

In an opinion piece for The Straits Times in Singapore, Esper summarized the progress his department has made in the year since releasing its Indo-Pacific Strategy Report.

Across the three pillars of preparedness, strengthening partnerships, and promoting a more networked region, he said the department has made "great strides," with "much more work" still to be done.

Specifically in the domain of strengthening partnerships, Esper said "we continue to build closer relationships with our Indo-Pacific allies and partners through security cooperation, information sharing and exercises."

He said "(i)t includes our efforts alongside South Korea to achieve the final, fully verified denuclearization of North Korea and an enduring peace on the Korean peninsula."

Japan, India, New Zealand and Thailand were also among the countries listed as partners.

Esper took direct aim at China for what he said was Beijing's destabilizing behavior in the East and South China Seas.

"While the US and our Indo-Pacific allies and partners work to preserve the free and open global system, China has tried to weaken and reshape it, contrary to our shared values and interests," he said.

"We stand with all of our partners and allies in the Indo-Pacific, big and small -- and together, we remain vigilant to resist the (Chinese Communist Party's) efforts to chip away at the sovereignty of other nations and undermine international rules and norms," he continued.

The defense secretary's articles comes at a time of heightened tensions between Washington and Beijing over a litany of issues, including trade, accountability for COVID-19, and civil liberties in Hong Kong.

Esper issued a rallying call to all US partners in the Indo-Pacific.

"Together, we must work to maintain a free and open Indo-Pacific, and defend these core principles: respect for sovereignty, peaceful resolution of disputes, adherence to international rules and norms, and the promotion of free and fair trade and investment," he said, describing them as not only American, but universal, values.

Esper also said US efforts in the Indo-Pacific helped the nation's response to the COVID-19 pandemic.

"Our collective battle against the virus, marked by new challenges and missions for our personnel, has reinforced the importance of a rules-based international order rooted in transparency, openness and shared values," he said.

In a veiled swipe at China, he added: "The virus has also shown us how far some are willing to go to shift blame, sow confusion and exploit a crisis, instead of collaborating in good faith to aid recovery." (Yonhap)