CANADA STOCKS-TSX ends flat as resource stocks gain, banks slip

* TSX down 3.33 points, or 0.02 percent, at 15,125.67 * Five of 10 main index sectors advance (Adds strategist comment, updates prices to close) By Alastair Sharp TORONTO, Sept 23 (Reuters) - Canada's main stock index ended little changed on Tuesday as worries about increasing tensions in the Middle East were overcome by gains in the natural resource sectors. The flat performance was in contrast to a slump in European indices and slips in the main U.S. stock markets. The