Japan has conveyed "grave concern" to China and Russia over a flight of strategic bombers during a Quad summit held in Tokyo, the government said Wednesday.

Six Chinese and Russian strategic bombers flew over the Sea of Japan, the East China Sea and the Pacific on Tuesday in apparent protest at the meeting that day of the leaders of Japan, the United States, Australia and India.

Calling the joint flight a "show of force" against Japan, Japan's top government spokesman, Chief Cabinet Secretary Hirokazu Matsuno, said the fact that it was conducted during the summit "raises the level of provocation."

Japanese Chief Cabinet Secretary Hirokazu Matsuno attends a press conference at the prime minister's office in Tokyo on May 25, 2022. (Kyodo) ==Kyodo

"We cannot overlook actions that heighten tensions in East Asia when Russia has already increased tensions in Ukraine," Matsuno said in a regular press conference.

He also said China dared to conduct the drill despite ongoing international efforts to stop Russia's aggression, and the government "strongly demanded China play a responsible role in maintaining peace and security in the international community."

Masahisa Sato, a lawmaker who leads the ruling Liberal Democratic Party's foreign affairs division, criticized Beijing, saying, "China has demonstrated itself as a rogue nation."

"We must show a stern stance based on international law against such an aberrant show of force," Sato said calling on the government to consider sailing defense force vessels to the Taiwan Strait.

Following the summit, the Quad leaders expressed opposition to changing the status quo by force in any part of the world. There is a strong sense in much of Asia, where China's assertiveness is increasingly being felt, the consequences of Russia's war in Ukraine will extend beyond Europe.

The long-distance joint flight, announced by the Japanese Defense Ministry late Tuesday, was the first such operation by Beijing and Moscow since November last year and the fourth confirmed by Japan.

Photo shows China's Xian H-6 bomber. (Photo courtesy of Taiwan's Defense Ministry)(Kyodo)

The ministry said that of the four Chinese warplanes, two were Xian H-6 bombers and the other two were believed to be a similar type. There were no intrusions into Japanese airspace by any of the six bombers involved in the flight.

The Chinese and Russian defense ministries announced that their warplanes conducted a "joint patrol" over the Sea of Japan and the East China Sea.

The Russian Defense Ministry was quoted by the Tass news agency as saying that the aircraft of both countries "acted strictly in accordance with the provisions of international law," and that "there were no violations of the airspace of foreign states."

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China, Russia fly 6 bombers over waters near Japan during Quad summit