* Shanghai shares off 0.2%, blue chips gain 0.2%
* Both indexes end August lower as trade war ramps up
* U.S. tariffs, official PMI due over the weekend
HONG KONG, Aug 30 (Reuters) - China stocks traded mixed on Friday, as investor optimism over signs of fresh Sino-U.S. trade negotiations was shadowed by Washington’s firm decision to go ahead with additional tariffs on Chinese imports starting Sept. 1.
** At the close, the Shanghai Composite index was down 0.2% at 2,886.24 points. The index closed 0.4% lower this week and dropped 1.6% in August, as a tit-for-tat escalation in the Sino-U.S. trade spat and a slump in the Chinese yuan dented sentiment. ** The blue-chip CSI300 index was up 0.3% on Friday, but down 0.6% week-on-week, bringing monthly losses to 0.9%. ** CSI300’s financial sector sub-index was higher by 0.1%, the consumer staples sector was up 1.8%, the real estate index was down 0.9% and the healthcare sub-index rose 0.8%. ** The smaller Shenzhen index dipped 0.7% and the start-up board ChiNext Composite index was weaker by 0.6%. ** The U.S. Trade Representative’s office on Wednesday said that on Sept. 1, U.S. Customs and Border Protection agency will begin collecting a 15% tariff on a portion of the list that contains over $125 billion of targeted goods from China, including smartwatches, bluetooth headphones, flat panel televisions and footwear. ** Ahead of the Sept. 1 deadline, Washington and Beijing indicated they would resume trade talks, with Trump saying some discussions were taking place and that more are scheduled. ** Meanwhile, China’s commerce ministry also said a September round of meetings was being discussed by the two superpowers, but said it was important for Washington to cancel a tariff increase. ** Factory activity in China is expected to have contracted for a fourth straight month in August, a Reuters poll showed, as the United States ratcheted up trade pressure and domestic demand remained sluggish. ** The official Purchasing Managers’ Index (PMI) for August is expected to be unchanged at 49.7 from July, but stay below the 50-point mark that separates expansion from contraction. The official PMI will be released on Saturday. ** “We remain cautious toward Chinese equities in general given the macro headwinds and increasing uncertainties in the U.S.-China trade negotiations,” Morgan Stanley analysts said in a note on Friday. ** Around the region, MSCI’s Asia ex-Japan stock index was firmer by almost 1%, while Japan’s Nikkei index closed up 1.2%. ** So far this year, the Shanghai stock index climbed 15.7% and the CSI300 surged 26.2%. ** About 19.40 billion shares were traded on the Shanghai exchange. The volume in the previous trading session was 17.86 billion. ** The Shanghai stock index is below its 50-day moving average and above its 200-day moving average. (Reporting by Noah Sin, Editing by Sherry Jacob-Phillips)