June 17 (Reuters) - Canada's main stock index opened lower on Monday, dragged down by materials and utilities stocks, while investors awaited crucial U.S. economic data and comments from Federal Reserve officials this week.

At 9:30 a.m. ET (13:30 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 70.06 points, or 0.32%, at 21,569.04. (Reporting by Nikhil Sharma; Editing by Shreya Biswas)