(Adds analyst comment, updates prices to close)
By Solarina Ho and Alastair Sharp
TORONTO, Sept 14 (Reuters) - Canada's main stock index fell on Monday over slumping oil prices and worries about the U.S. Federal Reserve's decision on interest rates this week.
With investors trying to position themselves ahead of the Fed decision, volatility in commodity prices due to worries over the Chinese economy, currency swings and mixed economic data also added to the market's uncertainties.
The Fed had been indicating it planned to hike rates at some point this year, but recent worries about global growth and lackluster Chinese economic data have raised the possibility the U.S. central bank could delay any increase to next year.
"It will be tough to take a definitive read on the markets this week until we get the Fed's decision," said Shailesh Kshatriya, associate director for client investment strategies at Russell Investments Canada.
"While it seems like a coin toss at the moment on if they raise rates, what will be more important is the language they use around whatever decision they make."
The Toronto Stock Exchange's S&P/TSX composite index closed down 108.13 points, or 0.8 percent, at 13,353.34. All of the 10 main sectors on the index were in the red.
Suncor Energy Inc was among the bigger drags on the index, falling 1.4 percent to C$33.59. Canadian Natural Resources Ltd gave back 1.6 percent to C$26.09. The overall energy group retreated 1.4 percent, in step with lower crude prices.
Bombardier Inc, which had soared some 58 percent last week after Reuters reported the company rejected an offer by Beijing Infrastructure to acquire a majority or full stake in its rail unit, gave back 10.8 percent to C$1.66 and was another top decliner. The industrials group retreated 1.1 percent.
Other areas weighing on the market included consumer discretionary stocks, which retreated 1.6 percent. (Additional reporting by Alastair Sharp and John Tilak in Toronto; Editing by Nick Zieminski and Grant McCool)