Japanese cabinet secretary general Yoshihide Suga said Tokyo had filed repeated diplomatic protests with Beijing over the presence of Chinese ships.
Tokyo and Beijing both claim uninhabited islands, but Japan has managed them since 1972.
Tensions on the rock chain, 1,200 miles (1,900 kilometers) southwest of Tokyo, have been simmering for years, and with claims going back hundreds of years, neither Japan nor China will shrink probably in a territory considered a national birthright in the two capitals. .
Chinese Foreign Ministry spokesman Zhao Lijian said on Monday that it was China’s inherent right to patrol the waters around the islands and Beijing urged Japan to stop undermining the country’s sovereignty. country.
Chinese government vessels have now spent 84 days in the waters around the islands, the Japanese coast guard said on Monday, but the actual intrusion into Japan’s territorial waters is raising the stakes on the dispute.
The Japanese coast guard said the two Chinese intrusions since Thursday – lasting 30 hours and 40 hours respectively – are the longest ranges that Chinese government ships have ever passed in Japanese waters around the islands. During these incursions, Chinese vessels were in the territorial waters of Japan, sailing approximately four to six miles (six to 10 kilometers) from the islands, said Japan.
The close proximity between the two sides exposes ships to the risk of collision, which could further increase tension if a military confrontation is provoked.
Such a scenario has sounded the alarm in the region, due to the risk of escalation. Under a mutual defense pact with Tokyo, the United States is obliged to defend the islands as part of Japanese territory.
Japan’s new defense ties with India could also heighten tensions between Tokyo and Beijing.
Late last month, Japanese Maritime Self Defense Force training vessels were drilled with Indian vessels in the Indian Ocean.
Asked at a press conference last month on the relationship between the increase in Chinese activities in the disputed islands and the Indo-Chinese military confrontation in the Himalayas, Japanese Defense Minister Taro Kono said that the region needed to better assess Chinese intentions.
“China is trying to change the status quo on the Indian border, in Hong Kong and in the East China Sea, the South China Sea. It is therefore easy to relate these questions. Obviously, the army is controlled by the Communist Party, so it must come from fairly senior officials of the Chinese Communist Party, “said Kono of the increase in Chinese military activities.
CNN’s Shawn Deng contributed to this report.