The latest spat between the world’s biggest and third-biggest economies threatens to add to a litany of other issues straining ties, including the value of China’s currency, trade protectionism and internet freedoms.

The official China Daily said US weapons sales to the self-ruled and democratic island “inevitably casts a long shadow on Sino-US relations”.

 

“China’s response, no matter how vehement, is justified. No country worthy of respect can sit idle while its national security is endangered and core interests damaged,” it said in an editorial.

 

“The US decision not only runs counter to the common dream of pursuing development and co-operation among the people on both sides of the Taiwan Straits, but also exposes the US’s usage of double standards and hypocrisy on major issues related to China’s core interests.”

 

Beijing considers Taiwan a breakaway province. Reflecting the intense emotions over the issue, Chinese internet users vented anger with calls to boycott top US exporter Boeing and other companies supplying weapon systems for the arms sales.

 

China has for years opposed US defence sales to Taiwan. For the first time, however, Beijing sought to pressure the US by punishing those private companies whose arms are involved in the Taiwan deals.

The People’s Daily, the Communist party mouthpiece, said in a commentary that the arms sales showed Washington’s “rude and unreasonable cold war thinking”.

 

“When it comes down to it, the United States is still drawing lines based on ideology and coming up with a million ways to stymie China’s development and progress,” the paper’s overseas edition said.

“If the United States stubbornly persists in this cold war thinking and ignores China’s core interests and grave concerns, the United States will further damage the development of bilateral ties and the great task of world peace. In the end, it will reap what it has sown.”

 

Yang Jiechi, Chinese foreign minister, said at the weekend that Washington’s planned $6.4bn arms package had “damaged China’s national security and great task of reunification (with Taiwan)”.

 

The US should “truly respect China’s core interests and major concerns, and immediately rescind the mistaken decision ... in order to avoid damaging broader China-US relations”, Mr Yang said.

 

China said it would impose unspecified sanctions on companies involved and reduce international co-operation with the US unless it cancelled the new arms package.

 

Beijing planned to postpone or partially halt some military co-operation, including a series of visits planned for this year – among them, one by Robert Gates, US defence secretary – along with meetings between top military commanders, and mutual visits by naval ships, Xinhua news agency reported.

 

US officials sought to downplay the dispute on Saturday.

 

“We regret that the Chinese government has announced that it plans to curtail military-to-military and other security-related exchanges and take action against US firms,” said PJ Crowley, the state department’s chief spokesman.

 

“We believe our policy contributes to stability and security in the region,” he said.

 

US officials have said Taiwan, which lags China in the balance of military power, needs updated weapons to give it more sway when negotiating with Beijing, which Taiwan says has aimed more than 1,400 short-range and mid-range missiles at the island.

 

Since 1949 when Nationalist forces fled to Taiwan after losing the mainland to Communist rebels, Beijing has demanded Taiwan accept unification, threatening to use force if necessary.

 

The Global Times, a popular Chinese newspaper with a nationalist slant, and Sohu, a Chinese web portal, have launched an online petition protesting the sales.

 

It calls for boycotts of US goods and has bitter denunciations of the US. Similar boycott calls for French and Japanese goods over the past few years during times of political tension soon petered out.