China has condemned Japan's decision to begin awarding gas drilling rights in a disputed part of the East China Sea.
Chinese foreign ministry spokesman Qin Gang called the action a provocation, and said China has the right to react to the move.
Tokyo's move comes at a time when relations with China are at a low over a new Japanese history textbook critics say glosses over Japan's wartime occupation of China and other nations.
On Saturday and Sunday, protesters damaged windows in the Japanese embassy in Beijing, and two Japanese students were attacked in a Shanghai restaurant. Meanwhile, the Chinese consulate in Osaka, Japan, has received threats against Chinese citizens in Japan.
Some information for this report provided by AFP and AP.