TORONTO (Reuters) - Toronto's main stock index fell yesterday after three days of gains as key commodity prices slipped and weak North American data splashed cold water on recent optimism about economic recovery.

The three main pillars of the TSX index - energy, down 0.6 percent, materials, down 0.8 percent, and financials, down 0.1 percent - led the decline.

On the energy side, shares dropped as US crude oil futures fell as traders expected Enbridge's big Canada-US crude pipeline to restart soon.

Suncor Energy was down 0.6 percent at C$33.70, while Canadian Natural Resources lost 1.7 percent to C$34.23. Enbridge gained 0.3 percent to C$52.24.

The market was also pressured by a report that showed Canadian manufacturing sales slid unexpectedly in July and data that showed a measure of New York state business conditions had slipped to the lowest level in more than a year. Another report showed US industrial output rose at a slower rate in August.

Takeover target Potash Corp. dropped 1.3 percent to C$150.52. China's state-owned Sinochem Corp. showed reluctance yesterday to make a bid for Potash, even as Beijing voiced concern over BHP Billiton's $39 billion bid for the Canadian company.

"With the energy sector weaker, with financials weaker, with materials weaker including Potash...it's not surprising that we're off. It's maybe surprising that we're not more off than we are," said John Kinsey, portfolio manager at Caldwell Securities.

The S&P/TSX composite index closed down 48.14 points, or 0.39 percent, at 12,144.84, with all of its main groups lower.

"It's just really in general a pause after the run-up that we've had. It's been a very good September so far," Mr. Kinsey said.

Weighing on banks, Lehman Brothers Holdings Inc said it is suing Canadian Imperial Bank of Commerce (CIBC) and dozens of other defendants to recover more than $3 billion it said it was deprived of as a result of its record bankruptcy two years ago. CIBC shed 0.5 percent to C$74.65.

Kinsey said losses in the group were likely cut by news that Bank of Montreal, up 0.2 percent at C$61.26, and Royal Bank of Canada, up 0.3 percent at C$54.49, both said they are seeking foreign assets two days after Canada's banking regulator gave banks the green light to begin spending capital.

The TSX index's gold sub-sector slipped 0.4 percent after a big rally on Tuesday on the back of record-high bullion prices.

Kinross Gold Corp. however, rose 2.7 percent to C$18.02, after a majority of its shareholders voted to approve the issue of shares and warrants to help fund the company's $7 billion acquisition of Red Back Mining Inc. Red Back rose 3.2 percent to C$32.32.