At least 19 major Japanese websites have fallen victim to cyber-attacks, thought to be from China, as a territorial dispute between the countries rumbles on.
Japan's National Police Agency says websites including those of the government, hospitals, universities and banks have come under DDoS attack since 11 September, when Japan purchased the previously privately owned Senkaku Islands.
The two nations have long disputed the sovereignty of the islands, which sit in the east China Sea, an area that contains oil and gas reserves.
The Japanese Times reports that hackers in China are responsible for the attacks, given that most of those under attack are listed on Chinese forums or chat sites.
Meanwhile, messages posted onto the affected sites criticise Japan with messages such as "Don't invade Diaoyu," along with pictures of the Senkaku Islands.
The police agency says it is possible that 300 other Japanese websites could be the targets of attacks, which are thought to be coordinated by up to 4,000 people.
The Japanese police and other authorities are investigating the cyber-attacks, and have strengthened observation of Chinese websites. They've urged those websites which have been hacked to protect themselves against further attacks.