China rejected Japan's "protest" against a Chinese newspaper that discussed Japan's sovereignty over Okinawa, saying on Thursday that media attention on the issue is a consequence of Japan's provocation over the Diaoyu Islands.

Observers said Japan has overreacted, urging Tokyo to reflect on historical problems rather than making protests.

Foreign Ministry spokeswoman Hua Chunying told reporters at a daily news briefing that "China cannot accept Japan's so-called negotiations or protests", saying China's stance on the issue has not changed.

"Academics have long paid attention to the history of Liuqiu and Okinawa," said Hua, adding that the issue is drawing a lot of attention recently because Japan has constantly made provocative actions over the Diaoyu Islands and infringed on China's sovereignty.

Japanese Chief Cabinet Secretary Yoshihide Suga told reporters at a news conference on Thursday that Tokyo has made an official protest against a People's Daily report on Wednesday, the Kyodo News Agency reported.

"We have protested both in Tokyo and Beijing over the commentary issued by the People's Daily, followed by a Chinese Foreign Ministry comment," a Japanese Foreign Ministry official in charge of Chinese affairs told AFP.

"We told them that if the Chinese government shares the position of casting doubt about Japan's ownership of Okinawa, we would never accept it and firmly protest it," he was quoted by AFP as saying.

"China replied to us that the view in the commentary was solely held by researchers," said the official.

Article of scholars

People's Daily published an article on Wednesday titled On the Treaty of Shimonoseki and the Diaoyu Islands Issue that discusses the issue of the island Okinawa.

The authors of the article, two scholars at the Chinese Academy of Social Sciences, said the Liuqiu islands between China and Japan were a "vassal state" of China before Japan annexed the islands in the late 1800s.

Hua said at a Wednesday news briefing that the Diaoyu Islands and affiliated islets are part of China's inherent territory and have never been part of Liuqiu or Okinawa.