Major Chinese telecoms companies Huawei Technologies and ZTE Corp have been in the crosshairs of the US-China trade war over national security concerns, but are also incurring the wrath of Washington for allegedly violating US sanctions on Iran. Here is a timeline of the major events: 14 July 2012: The FBI opens a criminal investigation into ZTE’s sale of banned US equipment to Iran. 7 March 2016: Trading of ZTE’s shares suspended in Hong Kong and Shenzhen after Reuters reported that the US Department of Commerce was about to slap export restrictions on the company for violating Iran sanctions. 8 March 2017: ZTE agreed to pay the US government US$1.2 billion in fines in exchange for suspending a seven-year denial of export privileges, which could be reactivated if any aspect of the deal was not met. 9 January 2018: Huawei Technologies confirmed that a deal to distribute its smartphones through US telecommunications carrier AT&T has been called off. Why Huawei and its CFO are caught in the middle of the US-China trade war 22 March 2018: US electronics retailer Best Buy reportedly prepares to halt the sale of Huawei phones from its online and offline shelves. 16 April 2018: The US Department of Commerce activated its seven-year exports ban on ZTE, denying the Chinese company access to vital US components and services for its smartphones and telecommunications gear. 25 April 2018: The US Justice Department is investigating Huawei for violating US sanctions in relation to Iran, The Wall Street Journal reported. 9 May 2018: After the 7 year export ban kicks in, ZTE announces it has ceased “major operating activities”. 6 June 2018: ZTE sends reprimand letters to 35 current and former employees involved in illegal sales to Iran and is seeking to claw back bonuses from those who have left the company. Arresting and arrested: Huawei founder’s two daughters 5 July 2018: Xu Ziyang, president of ZTE’s Telecom Cloud and Core Network product line, is named as the new CEO, as the company endeavours to get back in business after receiving the green light from US authorities to resume business 23 August 2018: Huawei and ZTE are excluded from building Australia’s 5G infrastructure after Canberra laid out new rules. 29 August 2018: Huawei appeals to US Federal Trade Commission (FTC) for a hearing into its restricted business opportunities, saying it has been unfairly targeted by the US government over national security concerns. 23 November 2018: US government exerting pressure on foreign allies to ditch Huawei gear that it considered a threat to cybersecurity, according to The Wall Street Journal. 30 November 2018: Spark, the biggest telecoms network operator in New Zealand, said the country’s intelligence agency blocked its proposal to use the Chinese firm’s equipment for its 5G development plans. 5 December 2018: Britain’s BT Group said it was removing Huawei equipment from the core of its existing 3G and 4G mobile operations and would not use the company’s gear in central parts of the next-generation 5G network. 6 December 2018 : Canadian authorities confirmed that Huawei’s chief financial officer Sabrina Meng Wanzhou was detained at the request of the US government, allegedly because she attempted to evade the US trade embargo on Iran. Follow @SCMPTech on Twitter for the latest China and Asia tech news.