Thousands of Chinese protesters on Saturday pelted stones at Japan's embassy in Beijing amid growing tensions between the two sides over a group of islands in East China Sea, where surveillance ships dispatched by Beijing asked Japanese Coast Guard vessels to leave the disputed area or face consequences.
The anti-Japan demonstrations were also reported from China's commercial hub of Shanghai, eastern city of Nanjing and Xian and Taiyuan in the north.
Protesters hurled stones at the Japanese embassy in Beijing and asked Tokyo to immediately vacate the disputed islands, media reports said.
The demonstrations follow Japan's recent announcement that it had bought the islands which it calls Senkaku, while China refers to the area as Diaoyu.
The Chinese demonstrators also denounced Tokyo's move to buy the islands.
Meanwhile, Chinese state-run television CCTV showed video footage of one of the officers of a maritime surveillance ship sending a radio message to the Japanese Coast Guard vessels to leave the area or face consequences, asserting that they were in Chinese waters.
"This is China's marine surveillance ship 50. Diaoyu island and its affiliated islands are China's inherent property," the officer said.
"China's sovereignty over these islands has a solid, historical and legal basis. The acts of your ships violate China's sovereignty and rights. Any one-sided act about Diaoyu and its affiliated islands from your side is illegal and invalid. Please stop such infringing acts, otherwise your side will have to bear whatever consequences were caused by your acts," he said.
Reports from Tokyo said Japanese Coast Guard too conveyed a similar message to Chinese ships, whose number is stated to be six at present.
This is perhaps the first time that Chinese maritime vessels, akin to Coast Guard, made public appearance in the waters of the islands.
Also, China's State Oceanic Administration (SOA) in Beijing announced a string of geographic coordinates of the Diaoyu Island and some of its affiliated islets, in a new move to affirm China's sovereignty.
The SOA announcement details the exact longitude and latitude of the Diaoyu island and 70 of its affiliated islets while publishing location maps, three-dimension effect graphs and sketch maps for the Diaoyu islands.
The announcement aims at helping the public understand the information concerning the Diaoyu island and its affiliated islets, the SOA said in a statement.
Also on Thursday, China's permanent representative to the United Nations Li Baodong met UN Secretary-General Ban Ki-moon and filed a copy of the Chinese government's Diaoyu islands baseline announcement with the world body.
The crisis took a serious turn after Japan bought the islands two days ago from a Japanese private party which held the rights over the territory.
The Chinese official media widely displayed pictures of its ships patrolling the waters while its navy conducted exercises with amphibious tanks in the Chinese coast practising how to take control of the islands.
According to a government statement, current patrolling activities are aimed at demonstrating China's jurisdiction on the Diaoyu islands and ensuring its maritime interests.
Chinese Assistant Foreign Minister Le Yucheng said yesterday these counter-measures by the Chinese government are an effective way to further uphold and strengthen China's sovereignty over the Diaoyu island and its affiliated islands.
He said China delimited and published the base points and baselines of the territorial sea of the Diaoyu island and its affiliated islands in accordance with the Law of the People's Republic of China on the Territorial Sea and the Contiguous Zone.
"This is in line with the UN Convention on the Law of the Sea (UNCLOS)," said Le.
The Japanese government's "nationalisation" of the Diaoyu islands has sparked protests and counter-measures in China.
The diplomatic standoff between Beijing and Tokyo has led to a series of cancelled visits and exchanges.
Already fears gripped the trade circles of both countries which have strongest trade in the region that touched $344 billion last year with Japanese exports to Chin totalling around $161 billion against $183 billion of China's exports to Japan.
A trip to Beijing later this month by a bipartisan group of Japanese parliamentarians was called off at the request of the Chinese host, reports from Japan said.
Over 220 travel agencies also stopped accepting reservations for tourists to visit each other's countries.
China has a major holiday period from late September to the first week of October and if other agencies follow the suit, Japan-bound tourism during the period could plummet, the official China Daily reported.
The Japanese government's moves over the Diaoyu Islands have scuttled bilateral cultural events, further dimming prospects for any fanfare to fete the 40th anniversary of ties.
Chinese pop singer Sun Nan cancelled a concert scheduled for Tokyo later this month, and Japanese singer-songwriter Shinji Tanimura has postponed a September 25 concert in Beijing.
Meanwhile, US Defence Secretary Leon Panetta, who is visiting Japan and China as part of his Asian tour this weekend, expected to urge both sides to step from the brink.
He would stop in Japan prior to his China visit.
The US, while asserting that the Diaoyu islands formed part of its defence treaty with Japan, has said it has not taken any position on the islands' ownership.