Japan and China have renewed their war of words over a group of disputed islets after Japan reported spotting a Chinese warship and an unidentified submarine in the East China Sea.
Japan lodged a protest with its neighbor after the submarine and the Chinese vessel approached what Tokyo considers as its territorial waters around the Japanese-administered Senkaku Islands, Japan's Defense Ministry said. Japanese Vice Foreign Minister Shinsuke Sugiyama issued a protest to the Chinese embassy in Tokyo.
The uninhabited islets are also claimed by China and Taiwan, where they are known as Diaoyu and Tiaoyutai, respectively.
The Chinese Foreign Ministry retorted by asking Japan to "stop making trouble over the Diaoyu Islands issue and to meet China halfway in accordance with the four principles agreed by both sides in 2014," a spokesman said, referring to a consensus on their differing stances reached by the two countries several years ago.
"The Japanese side can't change the objective facts of the Diaoyu Islands belonging to China in any way, and it can't shake the firmness and determination of the Chinese side in safeguarding its territorial sovereignty over Diaoyu Islands," spokesman Lu Kang said.
Lu also said that China noticed two Japanese ships approaching the disputed area.
Tokyo purchased three of the islets from a private owner in September 2011, sparking anti-Japan protests in dozens of Chinese cities and a boycott of Japanese products. The incident comes amid signs of improving bilateral relations between the two countries.
In late December, Toshihiro Nikai, secretary general of Japan's ruling Liberal Democratic Party, held talks with Chinese President Xi Jinping, inviting him to visit Tokyo this year.