Tokyo: Japan's Defense Ministry said Tuesday it has confirmed that the Chinese navy conducted firing exercises within Japan's exclusive economic zone on Sunday.

According to Philippines News Agency, it was the first time that the ministry had publicly acknowledged such a drill by the Chinese military in Japan's EEZ. The ministry also noted the presence of a Russian navy frigate nearby, which prompted the Japanese Maritime Self-Defense Force to engage in warning and surveillance activities. "We recognize the move as part of efforts to strengthen military cooperation between the Chinese and Russian militaries, and we are closely monitoring the situation with concern," Japanese Chief Cabinet Secretary Minoru Kihara stated at a press conference Tuesday.

The ministry and other sources reported that the MSDF detected three Chinese vessels and one Russian vessel sailing in a northeasterly direction at a point around 330 kilometers southwest of the remote Tokyo island of Okinotorishima in the Pacific around 2 a.m. Sunday. Of the three Chinese vessels, one missile destroyer conducted machine-gun drills within Japan's EEZ at a location some 180 kilometers southwest of the island.

The Japanese government, through diplomatic channels, communicated to the Chinese side that the drills could pose a danger to ships sailing nearby. Additionally, it was reported that the Chinese navy vessel issued a radio notification to nearby vessels immediately before the live-fire drills.

Japanese Defense Minister Shinjiro Koizumi, who is currently visiting Britain, mentioned in a speech on Monday that the Chinese and Russian militaries conducted live-fire exercises in Japan's EEZ. He also highlighted a recent string of joint operations by bombers from both nations near Japan, indicating a deepening military cooperation between China and Russia.