SHANGHAI, Aug 27 (Reuters) - China shares rose on Friday after investors took comfort in the central bank’s move to make its biggest weekly cash injection into the banking system since February, and as local authorities urged more financial support for retail and trading firms. The CSI300 index was up 0.8% at 4,837.90 points, by the end of the morning session, while the Shanghai Composite Index gained 0.5% to 3,518.83 points. The Hang Seng index added 0.5% to 25,546.37 points. The Hong Kong China Enterprises Index gained 1% to 9,025.53. ** China’s central bank injected 50 billion yuan ($7.71 billion) through seven-day reverse repos into the banking system on Friday for the third straight session. The weekly total injection is a net 120 billion yuan, the largest since the start of February. ** Financial institutions should do more to help retail, catering, and trading firms in the wake of recent domestic coronavirus outbreaks, the commerce ministry said on Thursday. ** Profit growth at China’s industrial firms in July grew at its slowest clip this year, adding to a recent batch of indicators highlighting loss of momentum in the country. ** “With the rising risk of a growth slowdown and the lack of flexibility in some key existing tightening measures, we believe the probability of an RRR cut is on the rise in the near term,” Nomura analysts said in a note. ** Shares of carmakers led the gains, with the sub-index up 4.3%, after Ministry of Industry and Information Technology of China organized a meeting to support accelerating the development of new energy vehicles. ** The insurance sub-index, the non-ferrous metal sub-index gained 2.1% and 2.6%, respectively. ** In Hong Kong, the Hang Seng Tech Index rose 1.1%. The index logged a weekly gain of 8.6%, the biggest since January. ** The industrial sub-index and the properties sub-index both rose 0.9%. ** Heavily indebted China Evergrande Group gained 3.1%, after hitting a six-year low in the previous session, as clear signs are now emerging that authorities at various levels are stepping in to avoid a hard landing for Evergrande. ** Its electric vehicle unit China Evergrande New Energy Vehicle Group soared 24.3%, the biggest daily percentage gain since Jan. 25. Reporting by Shanghai Newsroom, Editing by Sherry Jacob-Phillips Our Standards: The Thomson Reuters Trust Principles.