* SSEC -0.3%, CSI300 -0.3%, HSI -0.6% * HK->Shanghai Connect daily quota used 5.4%, Shanghai->HK daily quota used 2.4% * FTSE China A50 -0.4% SHANGHAI, Dec 8 (Reuters) - China and Hong Kong shares extended declines on Tuesday, dragged down by financial and transport firms, as Sino-U.S. tensions continued to weigh on the market. ** The CSI300 index fell 0.3% to 5,006.50 by the end of the morning session, while the Shanghai Composite Index lost 0.3% to 3,407.99. ** Among sectors, the CSI300 financials index and transport index shed 0.7% and 0.9%. ** In Hong Kong, the Hang Seng index dropped 0.6% to 26,344.96, while the Hong Kong China Enterprises Index lost 0.4% to 10,429.52. ** The Hang Seng financials index dropped 1.9%, following a 1.7% loss on Monday. ** The United States on Monday imposed financial sanctions and a travel ban on 14 Chinese officials over their alleged role in Beijing’s disqualification last month of elected opposition legislators in Hong Kong. ** Chinese Foreign Minister Wang Yi assured U.S. executives during a videoconference on Sunday that Beijing remained committed to the Phase 1 trade deal with the United States, the head of the U.S.-China Business Council said. ** Some market participants expected limited impact from Sino-U.S. tensions on the A-share market. ** “The impact from the Sino-U.S. relations (on the market) could decrease as the post-Trump era nears,” said Hu Yunlong, chief investment officer at Beijing Kaixing Asset Management Co. ** Hu said the recent retreat was mainly due to a “year-end effect”, where investors turn more cautious and book profits, while there are still worries over the coronavirus outbreak abroad. ** The market could continue to be rangebound as the year-end approaches when the liquidity conditions become relatively tight, Wanlian Securities said in a note. ** Around the region, MSCI’s Asia ex-Japan stock index was firmer by 0.10% while Japan’s Nikkei index was down 0.22%. (Reporting by Luoyan Liu and Andrew Galbraith; Editing by Rashmi Aich)