U.S. president Barrack Obama and the Japanese Prime Minister Shinzo Abe issued a joint statement on April 25, 2014. The statement claims that the U.S.-Japan Security Treaty applies to all Japan-administered territories, including the Diaoyu Islands. This is the first time a U.S. president has made such an unequivocal claim. That same day, the Chinese foreign ministry summoned the American and Japanese ambassadors respectively and made solemn representations over the issue.

Chinese netizens have expressed their indignation over the U.S.-Japan statement. Protests and criticism from Chinese netizens have proliferated online.

Many netizens take the view that the Chinese government should resolutely defend its territory. A netizen called "xueqingzhao2013" posted that he supports the Chinese foreign ministry and defense ministry’s determination to safeguard China's sovereignty over the Diaoyu Islands; the Diaoyu Islands have been Chinese territory since ancient times; the U.S./Japanese is doomed to failure given Japan’s illegal 'purchase' of the islands and the absurdity of the two countries signing an agreement over what is Chinese territory.

"Tianya Hechu Wang Shenzhou", another netizen, commented that the Diaoyu Islands are an integral part of China and that China has indisputable sovereignty over the islands; the Japanese actions on the islands are illegal and invalid. No one will sway us from our resolution to safeguard our territory and our maritime interests.

"China's Coastguard vessels should continue to patrol territorial waters surrounding the Diaoyu Islands, drive away any Japanese vessels, and defend our territory!" said a netizen called "Wo Ai Falali" (I love Ferrari).

Many netizens condemned the interrvention of the U.S., pointing out that the U.S. should not interfere in Chinese affairs.

"The Diaoyu Islands in the East China Sea have been an integral part of Chinese territory for centuries. The U.S. has no right to interfere. The recent U.S. statement is bound to damage Sino-Japanese relations and Sino-US relations, and poses a threat to security in the Asia-Pacific region," commented a netizen called "HappyS05S003".

A netizen called "Fanri Shijie Huaren Baodiao Lianmeng"(Anti-Japan World Chinese Alliance in Defense of the Diaoyu Islands) was equally confrontational: "The recent U.S. statement is irresponsible in terms of friendly and peaceful Sino-Japanese relations, and of Asia-Pacific security. Disputes relating to China’s own islands should be resolved by China itself. The U.S. makes a song and dance about freedom and democracy. But the DIaoyu Islands are Chinese territory. As the saying goes, "Do in Rome as the Romans do". You have to understand other people’s rules when you come to their home. Insist on being thoughtless, and exceed the boundaries of courtesy, and you will pay the penalty!"