Three Chinese warships have been seen near Japan and appear to be sailing an unusual route around the archipelago, according to Kyodo News – days after Russian vessels traversed nearby waters. Japan’s defence ministry said two Chinese guided-missile destroyers and a supply ship had on Monday sailed southwest through an area to the southeast of Chiba prefecture, Kyodo reported. They had reportedly entered the Sea of Japan from the Tsushima Strait, then headed into the Pacific Ocean via waters near Hokkaido last week. The warships then sailed through waters east of Miyagi county on Sunday and appeared to be circumnavigating the Japanese archipelago, according to the report. It comes after Japan’s defence ministry on Friday said seven Russian warships had passed near the Izu Islands south of Tokyo. The vessels had sailed south past Hokkaido in the Pacific Ocean and were spotted near the uninhabited Izu Islands on Thursday and Friday – the first time Russian warships had been in the area since October, according to Kyodo. Ten vessels from Russia and China sailed around Japan in a seven-day patrol in October, traversing the Sea of Japan, western Pacific and East China Sea and passing through several strategically important straits in the process, according to Chinese state media reports. Japan is on alert over growing military activity by Russia and China near its territory. Last month, Chinese and Russian strategic bombers conducted joint flights over waters near Japan – prompting it to scramble fighter jets in response – in what was seen as a protest over a Quad summit being held in Tokyo. Tensions have worsened between China and Japan in the past year as Tokyo has become more vocal in its support for Taiwan – which Beijing claims as part of its territory – and made what Beijing sees as “provocative” moves, like sending an active defence official to the island for information gathering. Earlier this month, China’s top diplomat Yang Jiechi said old problems in the relationship were now intertwined with new ones and urged the two nations to “grasp the right direction”, in a phone call with Japanese national security chief Takeo Akiba. The latest source of friction is apparent gas field exploration by Beijing in a contested area of the East China Sea, with senior officials from the two nations expected to hold talks on Thursday to discuss the issue, diplomatic sources told Kyodo on Saturday. Will fresh Sino-Japanese talks over China’s gas drilling end in deadlock again? Japan’s foreign ministry on Monday said the area is on the Chinese side of a Tokyo-proposed median line separating the countries’ exclusive economic zones in the sea and it had lodged a protest with the Chinese embassy in Tokyo. Tokyo fears Beijing’s unilateral development in the area may lead to the siphoning off of resources from beneath the Japanese side of the line. Meanwhile, relations between Japan and Russia have also deteriorated since Tokyo joined international sanctions over Moscow’s invasion of Ukraine in February. Hu Jiping, vice-president of the China Institutes of Contemporary International Relations, said the latest Chinese warship activity was being conducted in international waters. “Japan is sensitive about this as it is rare – but it is legal,” Hu said, adding that Tokyo was watching China’s more frequent military activity closely. Liu Jiangyong, an international relations professor at Tsinghua University, also said Japan would be keeping close watch on both Chinese and Russian military moves since it had labelled both nations as threats. He said Tokyo was also playing up the issue to win domestic support for a proposed increase to the defence budget this year.