One of Donald Trump's campaign promises was to impose a 45 percent tariff on imports from China if he became president. Today, the country's state-run Global Times warned such a move would result in repercussions that will affect the sale of iPhones and US cars in China.

The Times says (via The Guardian) that the president-elect would be "naïve" to follow through on his election promises of introducing the tariff and officially declaring China a currency manipulator. "China will take a tit-for-tat approach then," the newspaper said in an editorial. "A batch of Boeing orders will be replaced by Airbus. US auto and iPhone sales in China will suffer a setback, and US soybean and maize imports will be halted. China can also limit the number of Chinese students studying in the US."

The paper goes on to say that maintaining the current trade agreement between the countries is "a win-win situation," and if Trump does decide to change things, then "the new president will be condemned for his recklessness, ignorance and incompetence and bear all the consequences."

Trump spoke to Chinese president, Xi Jinping, just before the editorial was published. It was the first time that the two men had communicated with each other. In a statement, Trump's staff said: "During the call, the leaders established a clear sense of mutual respect for one another, and President-elect Trump stated that he believes the two leaders will have one of the strongest relationships for both countries moving forward."

As president, Trump could impose tariffs on specific goods, but no more than 15 percent and only for 150 days on all imported good - unless a state of emergency is declared. Like many of his pre-election statements, whether he follows through with the promise remains to be seen.

Last week, Tim Cook become the latest silicon valley leader to address Trump's presidency. The Apple CEO sent out an internal memo calling for unity among his employees. Trump spoke out against Apple's decision not to help the FBI unlock the San Bernardino iPhone earlier this year, and said he would force the company to make all of its devices in the US if he became president.