Tokyo, Japan - Chinese and Russian naval forces conducted provocative joint live-fire exercises within Japan's exclusive economic zone, including the use of machine guns, Tokyo said on Tuesday.

The incident on Sunday was the first time that Japan's defense ministry has spotted a live-fire drill by China within its exclusive economic zone and publicly disclosed it, according to Japanese media.

Tokyo sees the drill as part the Chinese and Russian militaries moving "toward strengthening their cooperation," Japan's top government spokesperson Minoru Kihara told a Tuesday briefing.

Relations between Japan and China have worsened since Japanese Prime Minister Sanae Takaichi angered Beijing in November with comments about Taiwanese independence and vowed to protect the island nation if attacked.

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On Sunday, the Chinese navy's Luyang III-class missile destroyer was seen conducting exercises 110 miles southwest of the Okinotori island, Japan's southernmost territory, alongside a Russian naval vessel, officials said.

A fleet comprising of three Chinese ships and a Russian navy frigate was first sighted about 205 miles southwest of the island, heading northeast.

Japan told Beijing via diplomatic channels that the drill "could have endangered the navigation of nearby ships," according to Kihara. In response, China's foreign ministry called the accusations "baseless."

"By smearing other countries for their legitimate and lawful actions and peddling the so-called external threat, Japan is seeking excuses for accelerating remilitarisation and challenging postwar international order," said Chinese Foreign Ministry spokesperson Lin Jian.

Chinese and Russian air forces jointly flew bombers over waters around Japan last month, and their navies also conducted a joint exercise this month.

The latest live-firing drill prompted Tokyo to mobilize by air and sea to surveil and monitor the situation, Kihara said.

"We will continue to monitor with concern the behaviors by Chinese and Russian vessels in the waters around our country," he told reporters.