SHANGHAI, Dec 17 (Reuters) - China's blue-chip stock index fell on Friday, notching its biggest weekly loss in three months, as local and foreign investors worried about U.S. and Chinese regulatory restrictions and a global resurgence of COVID-19 cases. ** At the close, the Shanghai Composite index was down 1.16% at 3,632.36 points. ** The blue-chip CSI300 index was down 1.59%. The index lost 1.99% for the week, its biggest weekly drop since mid-September. ** Adding to tensions between the United States and China, Washington on Thursday put investment and export restrictions on dozens of Chinese companies, including top drone maker DJI, accusing them of complicity in the oppression of China's Uyghur minority or helping the military. ** Washington still has not decided whether to block more sales of U.S. technology to Chinese chipmaker SMIC, sources told Reuters. SMIC shares were up nearly 1.8% in Hong Kong on Friday afternoon, but have fallen nearly 13% this month.

** A sub-index tracking A-shares of semiconductor firms slipped more than 3%.

** Foreign investors were net sellers of A-shares, with Refinitiv data showing outflows of 1.36 billion yuan ($213.43 million) through Stock Connect on the day.

** Consumer staples firms, including distillers favoured by foreign investors, ended down 2.59%.

** Energy firms fell 2% and the information technology sector lost 1.94%. ** The smaller Shenzhen index ended down 1.28% and the start-up board ChiNext Composite index was weaker by 1.608%. ** Around the region, MSCI's Asia ex-Japan stock index was weaker by 0.67%, while Japan's Nikkei index closed down 1.79%. ** At 0700 GMT, the yuan was quoted at 6.3696 per U.S. dollar, 0.01% weaker than the previous close of 6.369. ** So far this year, the Shanghai stock index is up 4.6% and the CSI300 has fallen 4.9%, while China's H-share index listed in Hong Kong is down 23.4%. Shanghai stocks have risen 1.92% this month. ($1 = 6.3720 Chinese yuan) (Reporting by Andrew Galbraith; Editing by Subhranshu Sahu)