Beijing, China - Following major announcements out of Japan on Sunday, China has hit back with a formal complaint and scathing comments, calling the US-Japanese relationship an issue of "grave concern."

The US joined with Japan over the weekend to announce a major upgrade to American military command, including a significant increase in nuclear deterrence as well as a range of other security measures.

Amid the announcements, US Secretary of Defense Lloyd Austin said the People's Republic of China has been engaging in "coercive behavior" and had been trying to "change the status quo" in the region, especially when it comes to Taiwan.

Austin's comments, as well as similar remarks made by the Japanese foreign minister, angered Beijing, which accused the US of meddling in China's internal affairs and smearing China on the world stage.

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Now, Beijing has issued a formal protest with Japan over negative comments made by Japanese diplomats during the US meeting.

Liu Jinsong, director-general of Asian Affairs at the Chinese foreign ministry, met with Chief Minister Yokochi Akira at the Japanese embassy in China to lodge the formal protest and talk about the "smears and attacks" made by Japan.

"China urges Japan to establish an objective and rational understanding of China, and stop making irresponsible remarks about China's internal affairs," Liu said.

Anger over comments revealed in the meeting documents worsened a diplomatic squabble that had begun between China and Japan when the Japanese foreign minister made a joint statement with the Quad targeting Chinese actions in the South China Sea.

"We are seriously concerned about the situation in the East and South China Seas and reiterate our strong opposition to any unilateral actions that seek to change the status quo by force or coercion," the statement read.

Responding to a journalist's question on upgrades to the US nuclear umbrella, Chinese foreign ministry spokesperson Lin Jian criticized Japan and the US for creating an "arms race."

Lin said "extended deterrence is a Cold War relic" and warned that nuclear collaboration between the US and Japan will only heighten the risk of regional conflict.

"Japan has long characterized itself as a victim of nuclear explosion and an advocate of a nuclear-weapons-free world," said Lin Jian.

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"All the while, it has been sitting comfortably under the US' nuclear umbrella, pursuing extended deterrence, and seeking 'nuclear deterrence.'"

"China calls on the US and Japan to abandon the Cold War mentality, reduce the role of nuclear weapons in national and collective security policies, and take concrete actions to uphold strategic stability and regional peace and security."