Chinese Ambassador to Japan Cheng Yonghua was summoned on Tuesday by the Japanese foreign ministry over the presence of Chinese maritime surveillance ships near the waters of disputed Diaoyu Islands.
This was the first diplomatic protest over the row by the new Japanese government under the lead of conservative Prime Minister Shinzo Abe. But Cheng asserted that China has indisputable sovereignty over the five uninhabited islands in the East China Sea and stated that China doesn't accept Japan's protest.
China's State Oceanic Administration said on Monday that a Chinese fleet of four marine surveillance ships continued to patrol territorial waters off the Diaoyu Islands.
Japanese Deputy Foreign Minister Akitaka Saiki summoned Cheng and lodged a strong protest with China's patrol, demanding that such intrusions not be repeated, according to the Kyodo News Agency.
At a press conference on Tuesday morning, Japanese Chief Cabinet Secretary Yoshihide Suga called the Chinese move an "extremely unusual incident and very regrettable." And Japanese Foreign Minister Fumio Kishida said Japan must strongly demand China to take measures to avoid any escalation of tension, Kyodo said.
Chinese foreign ministry spokesman Hong Lei said Tuesday that China does not accept Japan's protest.
"The Chinese vessels were carrying normal official duties in the waters of Diaoyu Islands, which are an inherent part of Chinese territory. But the Japanese side has repeatedly sent its ships and planes to enter China's territorial waters and airspace," Hong said.
"China has lodged a protest with Japan, demanding its government stop these illegal activities," he added.
Analysts said the summoning of the Chinese ambassador suggested the Abe cabinet would not relent in confrontation with China over the territorial disputes.
"Japan understands very well that its protest will not result in any changes in China's policy in the row. It is better for Japan to protest vocally than do nothing since it hasn't devised a comprehensive strategy for the Diaoyu disputes," said Gao Hong, deputy head of the Institute of Japanese Studies at the Chinese Academy of Social Sciences.
"Abe's new cabinet has never signaled it would correct the Japanese central government's mistake in 'purchasing' the Diaoyu Islands in September last year, which has led to heightened tensions between the two East Asian neighbors. It will only continue to confront China," Gao told the Global Times.
The Japanese government decided Monday to suspend two current defense programs, paving the way to revise its defense policy and increase the weapons purchasing budget, according to local media.
The outgoing US Defense Secretary Leon Panetta held phone talks with his Japanese counterpart Itsunori Onodera on Tuesday morning, and they agreed to strengthen their military alliance to deal with China.
However, a high-profile visit by Abe to Washington, his first overseas visit since returning to the position of prime minister, was postponed because of US President Barack Obama's busy schedule in preparation for his presidential inauguration ceremony on January 21.
Agencies contributed to this story