Japan recently sent a submarine to the South China Sea for military exercises for the first time, the Japanese defense ministry revealed Monday.

The attack sub Kuroshio participated in drills alongside three Japanese destroyers, including the Kaga helicopter carrier.

The move appears to have angered China, which warned Japan to "act with caution" and avoid damaging regional peace and stability.

A Japanese submarine recently joined up with three destroyers for drills in the disputed South China Sea, marking the first reported deployment of Japanese undersea warfighting assets to the contested region for exercises, Japan's defense ministry revealed Monday.

The Oyashio-class attack submarine Kuroshio participated in exercises with several other Japanese warships, including the Japan Maritime Self-Defense Force's Kaga helicopter carrier, last Thursday. The Kaga, which is accompanied by various escort ships and on a two-month tour of Southeast Asia and the Indian Ocean, recently drilled alongside the US Navy in the South China Sea. The Japanese sub practiced hunting enemy submarines in the exercise.

In response to the drills, Chinese Ministry of Foreign Affairs spokesman Geng Shuang asserted that Beijing "urges the relevant external country to respect the efforts made by regional countries to resolve the South China Sea issue through talks."

"Act with caution and don’t take any acts that could damage peace and stability in the region," he warned, according to Reuters.

Experts perceive Japan's efforts as an attempt to preserve the balance of power in the region as China's military power grows. "It’s part of a strategic message that Japan would like to send to China and the countries in the region," Narushige Michishita, an international security studies expert and a professor at the National Graduate Institute for Policy Studies in Tokyo, told The Wall Street Journal.

Given China's interest in enhancing its undersea warfare capabilities, the deployment of strategic underwater assets to the region is considered "very significant."

After the completion of the exercises, the Kuroshio visited Vietnam, an unprecedented visit demonstrating Japan's support for one of the South China Sea claimant states at odds with China. Japan does not claim territory in the South China Sea, but it is involved in a rather tense territorial dispute with China over the Senkaku/Diaoyu Islands in the East China Sea.

China claims the vast majority of the South China Sea, and has clashed with both other claimant states and foreign ships and planes operating in the area.

The UK Royal Navy amphibious assault ship HMS Albion recently found itself in a showdown with the Chinese military — a frigate and two Chinese helicopters — in the South China Sea after it sailed close to Chinese-occupied territories in the Paracel Islands.

The Chinese military has also issued radio warnings to US Navy ships and aircraft, as well as Philippine military aircraft that fly near Chinese-held territory. Neither the US nor the Philippines have allowed these warnings to impact their operations.