TORONTO (Reuters) — The Toronto Stock Exchange's main index skidded sharply for a third session yesterday, battered by worries about slowing global growth and the impact that will have on the demand for resources.

Concerns over weakness in the US labour market and a drop in prices for oil, gold and other metals also combined to knock the Toronto benchmark down more than two percent — bringing its losses so far this week to seven percent.

The price of crude, a key underlying factor for the energy-heavy index, fell $1.46 to $107.89 a barrel as worries over demand overshadowed a drop in US inventories. Canadian Oil Sands Trust was down five percent at C$44.95.

The materials sector, home to resource shares, also dragged as gold producers and other miners fell. Fertilizer firm Potash Corp of Saskatchewan slid 2.5 percent to C$160.37.

"It's not just the Toronto market, it's markets around the world," said Ian Nakamoto, director of research at MacDougall, MacDougall & MacTier.

"It's just a general lack of confidence in the overall market," Nakamoto said.

The S&P/TSX composite index closed down 323.58 points, or 2.46 percent, at 12,814.14 with all 10 of its main sectors ending lower

The materials and energy sectors gave up 3 percent and 2.3 percent, respectively.

Research In Motion, the maker of the BlackBerry, fell 5.6 percent to C$115.13 as the tech group was hurt by fears of softening corporate spending. The group as a whole lost 1.9 percent.

Data out of the United States added to the unease after a worse than expected report showed a steadily declining labour market, fuelling concerns about the economic prospects for Canada's biggest trading partner.

Shares of MDS Inc slid 5.6 percent to C$14.85 after the health sciences company reported a weaker third quarter and cut its full-year outlook.

The Canadian dollar weakened against US dollar yesterday, giving back all its gains from the previous day as oil prices fell and the greenback rallied.

Domestic bond prices, with no Canadian data to influence a move, rallied on a safe-haven bid as equity markets suffered steep losses.

The Canadian currency ended the North American session at C$1.0695 to the US dollar, or 93.50 US cents, down from C$1.0610 to the US dollar, or 94.25 US cents, at Wednesday's close.