This week saw another round of US-China tariffs unleashed after what seemed like a brief but precarious period of calm. Two Chinese government agencies on Thursday (October 9) announced multiple export control measures related to rare earths, which are key industrial minerals whose processing is largely dominated by China. Semiconductor exports will also come under greater scrutiny.In response, United States President Donald Trump wrote a lengthy post on Truth Social, describing the policy as “extraordinarily aggressive” and a “moral disgrace”. He also said a tariff of 100% will be imposed on Chinese goods from November 1, and the US “will impose Export Controls on any and all critical software.”On another front of their economic relations, China’s commerce ministry added 14 foreign organisations to its “unreliable entity list” on Thursday. Many of those firms were US-based. Further, US semiconductor giant Qualcomm is also now on the regulatory radar in China.Finally, we look at an ongoing political controversy in the United Kingdom, where two people were arrested for allegedly spying for China in 2023. The case was set to go on trial soon, but the charges were dropped last month. British Prime Minister Keir Starmer blamed it on how the previous Conservative government dealt with China.Here is a closer look at these developments:1. Clash over rare earths and tariffsThe Chinese government’s new export controls focus on technologies related to rare earths, requirements for overseas entities, and items related to lithium batteries (used in electric vehicles), among other things.An official spokesperson framed the decision as a legitimate action and criticised the retaliatory tariff announcement from the US. “The United States has been overstretching the concept of national security, abusing export control, taking discriminatory actions against China, and imposing unilateral long-arm jurisdiction measures on various products, including semiconductor equipment and chips,” a report in state media Xinhua said.Read last week's tracker | China This Week | Attracting STEM talent to China, and reading new PMI dataThey further argued that since the latest round of their bilateral trade talks in Madrid in September, the US had introduced “a string of new restrictive measures targeting China”. Reuters reported earlier this week that US lawmakers called for broader bans on selling chipmaking equipment (which powers electronic devices and is crucial for developing artificial intelligence) to China.Story continues below this adUPSHOT: Officially, the Commerce Ministry claimed that the move was aimed at regulating “dual use”: “Certain overseas organizations and individuals have transferred rare earth items originating from China… the materials are directly or indirectly utilized in military and other sensitive fields, causing significant harm or potential threats to China’s national security and interests, while having an adverse impact on international peace and stability”.Rare earths matter for several important industries, as we have previously explained. While this is not the first time that China has leveraged them, the current restrictions are much wider in scope.They are also being seen as a bargaining chip ahead of the planned meeting between Trump and Chinese President Xi Jinping in South Korea for the Asia-Pacific Economic Cooperation Forum (APEC) later this month. It would be their first meeting in Trump’s second term.In the near future, however, it could affect a range of industries, and shows just how difficult the task of managing relations between the world’s two biggest economies has become.Story continues below this ad2. Additions to Unreliable Entity List, Qualcomm’s problemsAn official statement said that some of the 14 companies now being added to the list carried out military and technological cooperation with Taiwan, the island that China considers its own territory. Or, they were found to have “made malicious remarks about China, and assisted foreign governments in suppressing Chinese companies”.Separately, on Friday, China’s top market regulator said that it had launched an investigation into Qualcomm over anti-monopoly law violations. It said that Qualcomm admitted to not having informed Chinese authorities when it completed its acquisition of Israel’s Autotalks, another semiconductor company, in June.UPSHOT: The list in question exists for the stated purpose of safeguarding national sovereignty, security and development interests, and maintaining fair and free trade. If foreign companies are found to have violated regulations, they can be restricted from operating within China. In practice, it has been utilised as the geopolitical tensions between Western nations and China have risen.Similarly, the Qualcomm investigation has commonalities with a case against the US AI chipmaker giant Nvidia. In September, Chinese authorities said the company violated anti-monopoly laws, which were linked to Nvidia’s purchase of an Israeli-American network and data transmission company, named Mellanox Technologies.Story continues below this adQualcomm, for its part, has stakes in maintaining its business in China. According to a Wall Street Journal report, “Nearly half its revenue came from China in fiscal 2024.”3. China at centre of UK spy sagaThe case concerns two men: Christopher Cash, 30, a former director of the China Research Group think tank and parliamentary researcher, and Christopher Berry, 33, a teacher who earlier worked in China. They were accused of “gathering and providing information prejudicial to the safety and interests of the state between December 2021 and February 2023,” the BBC reported.Both men denied the charges, as did the Chinese embassy in the United Kingdom, while efforts began to prosecute them. However, the charges came under the Official Secrets Act, where prosecution can proceed if the information passed on was useful to an “enemy”.China does not come under that definition, and the case has led to the Conservatives and the Labour Party trading allegations. While Starmer blamed his predecessors for how they dealt with China, Conservative MPs are alleging that he has yet to proceed with the case to avoid offending the country.Story continues below this adUPSHOT: The incident is the latest amid a larger perception of China in UK politics. In 2023, the head of the intelligence agency MI5, Ken McCallum, said there had been a “sustained campaign” of Chinese espionage on a “pretty epic scale”.In another example, China is looking to establish a new embassy complex in London, spanning across 20,00 sq metres, and Xi reportedly spoke about it with Starmer in 2024. However, area residents have cited security threats and opposed the plan. For the government, it adds to the challenge of managing these concerns while ensuring a working relationship with China.