Japan warned China on Tuesday that ties were "deteriorating markedly" over disputed East China Sea islets, and China's envoy in Tokyo reiterated Beijing's stance that the specks of land were its territory and called for talks to resolve the row.
Tensions between Asia's two largest economies have risen since Japan saw an increasing number of Chinese coastguard and other government ships sailing near the disputed islets, called Senkaku in Japan and Diaoyu in China, over the past few days.
Japanese Foreign Minister Fumio Kishida called in Chinese ambassador Cheng Yonghua for the second time since Friday and told him that China was trying to change the status quo unilaterally, a Japanese foreign ministry statement said.
It also said Kishida told Cheng that the environment surrounding Sino-Japanese ties was deteriorating markedly.
Cheng said after the meeting that he told Kishida the islands were an integral part of China's territory and that the dispute should be resolved through diplomacy and dialog.
"I told him that ... it is natural that Chinese ships conduct activity in the waters in question," he told reporters.
"I also told him both countries need to work on dialog through diplomatic channels so as not to make things more complicated and escalated," Cheng said.
Kishida summoned Cheng after the latest flare-up in tensions over dozens of Chinese vessels that sailed near the islands at the weekend. Cheng was also called in by Japanese Vice Foreign Minister Shinsuke Sugiyama on Friday.
The flurry of Chinese incursions into the waters follows a period of sustained pressure on China about its activities in the South China Sea, and Chinese criticism of what it saw as Japanese interference in that dispute.
The United States, its Southeast Asian allies and Japan have questioned Chinese land reclamation on contested islands in the South China Sea, particularly since an international court rejected China's historic claims to most of that sea last month.
China has refused to recognize the court ruling on a case brought by the Philippines. Japan called on China to adhere to it, saying it was binding but Beijing warned Japan not to interfere.
Ties between China and Japan, the world's second and third largest economies, have been plagued by the territorial row, the legacy of Japan's wartime occupation of parts of China and regional rivalry.