According to recent reports, numerous more Chinese agencies and government-backed firms have instructed staff to stop bringing iPhones to work, accelerating the country’s efforts to block tech giants from parts of the world’s largest mobile market. Apple’s shares (AAPL) slid 0.7% in the premarket today. iPhone Ban Accelerates Across Chinese Agencies and State-backed FirmsApple shares slipped 0.7% in premarket trading Monday after reports revealed that China has extended its ban on iPhone devices for state employees.According to Bloomberg, more Chinese agencies and state-backed companies across at least eight provinces have instructed their employees not to bring Apple iPhones and other foreign electronic devices to work. Instead, the report added that the staff were asked to use local brands. This month, smaller companies and agencies in provinces such as Zhejiang, Shandong, Liaoning, and central Hebei, where the world’s largest iPhone factory is located, issued instructions regarding using foreign devices.   China – Apple’s Biggest Foreign MarketChina has been striving to reduce its dependence on foreign technologies for more than a decade, asking state-backed firms and banks to begin using local software and promote domestic chip manufacturing. However, devices made by Apple have been of particular focus for Chinese officials. Earlier this year, the government wiped $200 billion of Apple’s market cap after announcing plans to expand a ban on using iPhones to state-backed agencies and affiliated companies.The move was significant because the world’s biggest company sees China as its largest market and global production base. It reported record June quarter sales from China, from -3% in March to +8%. However, the ban’s impact was only short-term because it was limited to government officials. The extension of the embargo could pose a bigger threat to the iPhone maker in China and other mega-cap tech giants that rely heavily on the world’s second-biggest economy. It remains unclear how many government agencies have specifically issued verbal directives. Meanwhile, different organizations will likely vary in how strictly they enforce the ban, with some prohibiting Apple devices from the workplace and others forbidding their use altogether.  More By This Author:Three Indicators That Show Promise For A Soft Landing Rivian Vs. Tesla: Which EV Stock Offers More Opportunity For GrowthMarket Braces For ‘Triple Witching’ Friday As Over $5T In Contracts To Expire