March 20 (Reuters) - Canada's main stock index fell at open on Friday in broad sectoral declines and was on track for a third straight weekly loss, as cautious investors monitored developments in Middle East conflict, which is nearing its fourth week.
At 09:31 a.m. ET, the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 0.4% at 31,731.87.