In the third year of the war in Ukraine, NATO is set to deepen relations with its four Indo-Pacific partners, which, although not part of the military alliance, are gaining prominence as Russia and China forge closer ties to counter the United States and the two Koreas support opposing sides of the conflict in Europe.

The leaders of New Zealand, Japan and South Korea for the third year in a row will attend the NATO summit, which starts Tuesday in Washington, DC, while Australia will send its deputy prime minister. China will be following the summit closely, worried by the alliance's growing interest beyond Europe and the Western Hemisphere.

"Increasingly, partners in Europe see challenges halfway around the world in Asia as being relevant to them, just as partners in Asia see challenges halfway around the world in Europe as being relevant to them," Secretary of State Antony Blinken said last week at the Brookings Institution.

America's top diplomat said the US has been working to break down barriers between European alliances, Asian coalitions and other partners worldwide. “That's part of the new landscape, the new geometry that we've put in place.”

Countries with shared security concerns are strengthening ties as competition escalates between the United States and China. Washington is trying to curb Beijing's ambition to challenge the US-led world order, which the Chinese government dismisses as a Cold War mentality aimed at containing China's inevitable rise.

On Monday, Beijing responded angrily to unconfirmed reports that NATO and its four Indo-Pacific partners are expected to release a document laying out their relationship and ability to respond jointly to threats from cyberattacks and disinformation.

Lin Jian, a spokesman for the Chinese foreign ministry, accused NATO of “breaching its boundary, expanding its mandate, reaching beyond its defence zone and stoking confrontation”.

The war in Ukraine, which has pitted the West against Russia and its friends, has bolstered the argument for closer cooperation between the US, Europe and their Asian allies. “Ukraine of today may be East Asia of tomorrow,” Japanese Prime Minister Fumio Kishida told the US Congress in April.

The US and South Korea accused Pyongyang of supplying Russia with ammunition, while Russian President Vladimir Putin visited North Korea last month and signed a pact with leader Kim Jong Un that envisions mutual military assistance.

South Korea and Japan, meanwhile, are sending military supplies and aid to Ukraine. The US also says China is providing Russia with machine tools, microelectronics and other technology that allow it to make weapons to use against Ukraine.

South Korean President Yoon Suk Yeol will bring to Washington “a strong message regarding the military cooperation between Russia and North Korea and discuss ways to enhance cooperation among NATO allies and Indo-Pacific partners”, his principal deputy national security adviser, Kim Tae-hyo, told reporters on Friday.

New Zealand Prime Minister Christopher Luxon said discussions would “focus on our collective efforts to support the rules-based system”.

The partnership does not make NATO a direct player in the Indo-Pacific but allows it to coordinate with the four partners on issues of mutual concern, said Mirna Galic, senior policy analyst on China and East Asia at the US Institute of Peace. For example, she wrote in an analysis, they can share information and align on actions such as sanctions and aid delivery but do not intervene in military crises outside of their own regions.

The NATO summit will allow the United States and its European and Indo-Pacific allies to push back against China, Russia, North Korea and Iran, according to Luis Simon, director of the Centre for Security Diplomacy and Strategy at Vrije Universiteit Brussel.

“The fact that the Euro-Atlantic and Indo-Pacific alliances are structured around a clear anchor — US military power — makes them more cohesive and gives them a strategic edge as compared to the sort of interlocking partnerships that bind China, Russia, Iran, and North Korea," Simon wrote in a commentary last week on War On the Rocks, a defence and foreign affairs website.

Beijing is worried by NATO's pivot to the east, said Zhu Feng, dean of the School of International Studies at Nanjing University in eastern China. Beijing has insisted that NATO not interfere in security affairs in the Indo-Pacific and that it should change its view of China as a strategic adversary.

“NATO should consider China as a positive force for the regional peace and stability and for global security,” Zhu said. “We also hope the Ukraine war can end as soon as possible ... and we have rejected a return to the triangular relation with Russia and North Korea.”

“In today's volatile and fragile world, Europe, the US and China should strengthen global and regional cooperation,” Zhu said.

NATO and China had little conflict until tensions grew between Beijing and Washington in 2019, the same year the NATO summit in London raised China as a “challenge” that “we need to address together as an alliance".

Two years later, NATO upgraded China to a “systemic challenge” and said Beijing was “cooperating militarily with Russia”.

After Russia invaded Ukraine in 2022, leaders of Japan, South Korea, Australia and New Zealand attended a NATO summit for the first time, where statements noted the geopolitical challenges China poses. Beijing accused NATO of “cooperating with the US government for an all-around suppression of China".

Now, Beijing is worried that Washington is forming a NATO-like alliance in the Indo-Pacific.

Chinese Senior Col. Cao Yanzhong, a researcher at China's Institute of War Studies, asked US Defence Secretary Lloyd Austin last month whether the US was trying to create an Asian version of NATO by emphasising partnerships and alliances.

They include a US grouping with Britain and Australia; another with Australia, India and Japan; and one with Japan and South Korea.

“What implications do you think the strengthening of the US alliance system in the Asia-Pacific will have on this region's security and stability?” Cao asked at the Shangri-la Dialogue security summit in Singapore.

Austin replied that the US was simply working with “like-minded countries with similar values and a common vision of a free and open Indo-Pacific".

Beijing has its own conclusion.

“The real intent of the US Indo-Pacific strategy is to integrate all small circles into a big circle as the Asian version of NATO in order to maintain the hegemony as led by the United States,” Chinese Lt. Gen. Jing Jianfeng said at the forum.