Japanese Prime Minister Yoshihiko Noda called on Beijing to ensure Japanese citizens in China were safe. Demonstrations against Tokyo took place across China last weekend as the countries spar over a group of disputed islands.
The countries have extensive trade ties but sovereignty over the islands, known in Japan as the Senkaku Islands and in China as Diaoyu, has been a source of contention. Tokyo has said it would purchase the uninhabited, but energy-rich, islands.
Hong Lei, a spokesman for the Chinese Foreign Ministry, called on Tokyo to listen to Beijing's position on the islands.
"We once again demand the Japanese side to immediately stop all acts that infringe upon China's territorial sovereignty and return to the track of negotiations for the settlement of the controversial issues," he was quoted by China's official Xinhua News Agency as saying.
U.S. Defense Secretary Leon Panetta warned from Tokyo the issued may "blowup" should there be a provocation on either side.
"And so it is the responsibility of those countries involved to try to resolve these issues peacefully," he said in a statement.