Japan has urged China not to escalate a conflict over natural gas exploration in a disputed area of the East China Sea.
Japan announced Wednesday it will begin reviewing applications for exploring for deep sea natural gas fields in the area. Beijing, which also claims exploration rights, called the move a provocation.
Japanese Prime Minister Junichiro Koizumi said Thursday, China should not overreact to a project that could benefit both countries.
Tokyo's relations with China were already at a low over a new Japanese history textbook that critics say glosses over Japan's wartime occupation of China and other nations.
Several Japanese government agencies reported cyber attacks on their web sites Thursday. Earlier this week there were violent protests in China against Japan, and a Chinese consulate in Japan, has also received threats.
Some information for this report provided by AP, AFP and Reuters.