China reacted with outrage on Monday at Japan's purchase of a disputed island chain in the East China Sea, prolonging a standoff which has blighted bilateral ties and raised regional tensions in recent months.
Beijing sent two patrol ships to waters surrounding the islands--which are known as Diaoyu in China and Senkaku in Japan--to reassert its claim after the Japanese government spent U.S. $26.18 million to acquire the three uninhabited islands from a Japanese family that has owned them since the 1970s.
In a growing dispute that further threatens ties between Asia's two biggest economies, China accused Japan of "playing with fire" over the long-simmering row, warning that its military stood ready to "defend our national sovereignty."
"This act is a severe infringement of Chinese territorial sovereignty," the official Xinhua news agency quoted defense ministry spokesman Geng Yansheng as saying on Tuesday.
Geng said the Diaoyu Island and its affiliated islands are China's inherent territory, citing "sufficient historical and jurisprudential evidence" to prove it, the report said.
"The Chinese government and armed forces stand firm and are unshakeable in its determination and will safeguard sovereignty over the nation's territories," Geng said.
Meanwhile, Japanese foreign minister Koichiro Gemba said that the purchase served the purpose of "peaceful and stable maintenance" of the islands.
"We cannot damage the stable development of the Japan-China relationship because of that issue. Both nations need to act calmly and from a broad perspective," he told reporters after a cabinet meeting approved the transaction.
Currently, the islands, which lie close to fishing grounds and potentially rich maritime gas fields, are administered by the Japanese coastguard.
Last month, the coastguard detained and deported a group of Chinese activists who landed on the islands, sparking off the long-running territorial dispute, which appears to be hurting economic ties between the two countries.
Chinese officials have said that car sales in the world's biggest auto market may have been hit, as Chinese consumers move to boycott Japanese goods in protest over the dispute.
In spite of the political posturing, the ruling Chinese Communist Party has moved to tone down nationalist rhetoric in recent weeks, following massive anti-Japanese protests around the country last month and an attack on the Japanese ambassador's car.
The protests flared in more than a dozen Chinese cities after a group of Japanese right-wing lawmakers and other nationalists landed on the largest island in a chain in the East China Sea and unfurled Japanese flags.
Their actions emulated those of 14 pro-China activists who had made the same gesture during their trip last week to the islands, called Senkaku in Japan and Diaoyu in China. They were arrested for illegal entry and sent home by the Japanese authorities.
Smaller protests took place in Beijing and other Chinese cities in reaction to the purchase on Tuesday.
In the eastern province of Shandong, "thousands" of people took to the streets after the news was announced, protesters said.
"They gathered outside a furniture store," said one participant surnamed Zhang. "There were thousands of people there; I heard 2,000 or 3,000."
"It was pretty busy, but not everyone there was taking part in the demonstration."
He said the protesters felt they had no other way to express their opinion on the dispute.
"We had no other way but to stage a march, to let the government know how people feel about this," Zhang said. "Of course we are on China's side."
'Protect the Diaoyu' movement
Meanwhile, U.S.-based Diaoyu activist Dai Qi said that the Diaoyu movement wasn't only limited to mainland China, nor to Taiwan, which also claims the chain as its own.
"The Protect the Diaoyu movement didn't start in mainland China, nor did it start in Taiwan," he said. "Actually, it started overseas, and the students [who took part] were all from Taiwan because there weren't any from the mainland back then."
He said the overseas movement was keen to avoid politicizing the issue, however. "We are purely about protecting the Diaoyu, and we don't gather under any political banner," he said.
The new tensions draw parallels with Beijing's disputes with Southeast Asian nations over territorial claims in the South China Sea.
China's rapid defense buildup on the back of its fast growing economy has led to concerns it could unleash its military might to impose its territorial claims on unwilling, smaller neighbors.
Reported by Wen Yuqing, Wei Ling, and Wei Ling for RFA's Cantonese service and by CK for the Mandarin service. Translated and written in English by Luisetta Mudie.