When Chinese Vice President Xi Jinping called Tokyo's territorial claims on a group of East China Seas island "a farce," he echoed national sentiment of protesters who took to the streets in anti-Japan protests in recent weeks.
"Japan should rein in its behavior, not utter any words and prevent any acts that undermine China's sovereignty and territorial integrity," said Xi -- who is expected to become China's new president next month -- at a Wednesday meeting with U.S. Defense Secretary Leon Panetta, state media reported.
As Beijing's presumptive new leader wades into the Japan-China dispute, analysts say the stakes are being raised in a dispute that is largely being led by nationalist fervor rather than government policy or underlining economic interests. And the détente that usually follows these territorial disputes is muddied by the leadership change in Beijing expected next month.
"This is where it's becoming dangerous," said Alan DuPont, defense expert at the University of New South Wales. "No incoming Chinese leader can be perceived to be weak on territorial claims."
On Monday, the Japan Coast Guard said two Chinese surveillance ships entered its territorial waters, while 10 other Chinese ships patrolled nearby. Meanwhile, China announced Sunday it was postponing planned celebrations later this month marking the 40th anniversary of normalization of relations between Beijing and Tokyo.
The bellicose rhetoric also charts the rise of an assertive China and a sea change in the forces shaping Pacific politics that are writ small in the battle over the uninhabited island chain, known as Diaoyu in China and Senkaku in Japan.
"China's feeling more confident both in its position and in its right to the area both legally and politically," Mark Valencia, a fellow at the National Asia Research Program and expert on the South China Sea dispute. "And nationalism in China has gained strength and influencing the government."
Rising tensions in China waters
The East China Sea isn't the only flashpoint for territorial tensions among China and its neighbors. The South China Sea is dotted with hundreds of largely uninhabited islands and coral atolls, many of which have competing claims from China, Vietnam, the Philippines, Malaysia, Brunei and Taiwan. Just like the friction with Japan, there have been increasing incidents of tension between China and its South China Sea neighbors over island claims.
In 2011, Vietnam claimed that Chinese patrol boats cut cables from PetroVietnam boats during oil and gas surveys in disputed waters. Beijing said that Vietnamese vessels have been illegally surveying in Chinese waters and harassing Chinese fishing boats. The same year Philippines also reported boats cutting cables of a survey ship and threatening to ram its boats.