The United States has issued its first criticism of China after Chinese fighter jets intermittently locked their radar on Japanese military aircraft over international waters, an incident that has intensified tensions between the two Asian neighbors.

“China’s actions are not conducive to regional peace and stability,” a State Department spokesperson said on Dec. 9, referring to the radar incident on Dec. 6.

“The U.S.–Japan Alliance is stronger and more united than ever. Our commitment to our ally Japan is unwavering, and we are in close contact on this and other issues.”

The run-in happened over the high seas of Japan’s Okinawa Island and lasted about 30 minutes across two encounters on Dec. 6, according to the Japanese defense ministry.

The following day, Japanese Vice Foreign Minister Funakoshi Takehiro summoned Chinese Ambassador Wu Jianghao and “made a strong protest that such dangerous acts are extremely regrettable,” according to a ministry statement.

Japanese Chief Cabinet Secretary Minoru Kihara welcomed the State Department’s comments, saying they “demonstrate the strong U.S.–Japan alliance.”

The Chinese regime has rebuffed Tokyo’s account of the incident. According to Chinese state-run media outlet Xinhua, Wang Xuemeng, a spokesperson for the Chinese People’s Liberation Army Navy, said on Dec. 7 that Japanese aircraft had repeatedly approached and harassed the Chinese navy as it was conducting carrier-based flight training east of the Miyako Strait.

Tensions between China’s communist regime and Japan have rapidly escalated in the past month, as Beijing has been applying economic pressure and engaging in military coercive tactics against Japan since Japanese Prime Minister Sanae Takaichi’s remarks on Taiwan on Nov. 7. That day, Takaichi told parliamentarians that a Chinese attack on Taiwan would constitute a “survival-threatening situation” for Japan and could trigger a military response from Tokyo.

The Chinese Communist Party claims Taiwan as a part of its territory and has not ruled out using military force to take control of the self-governing island, which is located about 69 miles east of the Japanese island of Yonaguni.

In an X post on Dec. 10, Taiwanese President Lai Ching-te criticized China for its recent “military provocations” near Japan and across the region.

“We stand together with democratic partners in opposing these actions & remain resolute in our determination to safeguard peace,” he wrote.

Lai recently announced a proposed defense budget of $40 billion to counter China’s potential military activity aimed at seizing the island by 2027.

US Support

U.S. Ambassador to Japan George Glass has publicly expressed support for Japan in several social media posts in recent weeks. For instance, on Nov. 20, Glass reaffirmed U.S. support for Tokyo after China announced a ban on Japanese seafood.

Glass reaffirmed the bilateral ties on Dec. 8, saying that the two countries established an “indestructible partnership” 65 years ago and that the alliance “is stronger and more united than ever,” according to his X post.

In the same post, Glass said the U.S. commitment to the U.S.–Japan alliance is reaffirmed in President Donald Trump’s newly released National Security Strategy, which describes alliances in the Indo-Pacific as the “bedrock of security and prosperity.”

The State Department previously voiced support for Japan after the diplomatic dispute began. On Nov. 20, State Department spokesperson Tommy Pigott described the alliance as the “cornerstone of peace and security in the Indo-Pacific.”

A bipartisan group of lawmakers has also voiced support for Japan.

On Dec. 8, Rep. Gregory Meeks (D-N.Y.), ranking member of the Foreign Affairs Committee, and Rep. Ami Bera (D-Calif.), ranking member of the committee’s subcommittee on East Asia and the Pacific, sent a letter to Trump asking the president to provide tariff relief to Japan amid what they described as “escalating economic and military coercion against Japan.”

The current U.S. baseline tariff on most Japanese imports is 15 percent, following a trade deal signed by the two sides in September.

“Providing tariff relief to Japan would also send a clear message that the United States rejects the normalization of Beijing’s coercive trade tactics and is prepared to back its allies when they are targeted for exercising their sovereign rights,” the two lawmakers wrote.

More Chinese coast guard vessels “patrolled” the waters of Japan-administered Senkaku Islands, which are known as the Diaoyu Islands in China, on Dec. 10, according to China’s state-run media. Beijing carried out similar patrols of the waters on Nov. 15.

Trump, who met with Chinese leader Xi Jinping on the sidelines of the Asia-Pacific Economic Cooperation summit in South Korea in October, is expected to visit China in April next year.

Reuters contributed to this report.