Photo: The Canadian Press. All rights reserved.

The head offices of Canada's biggest banks are shrouded in fog in Toronto's financial district on December 30, 2011. THE CANADIAN PRESS/Frank Gunn

The Toronto stock market was slightly lower at the open as potential damage from the looming U.S. fiscal cliff continued to cast a shadow over trading while investors also took in a strong earnings report from tech bellwether Cisco Systems.

The S&P/TSX composite index declined 10.6 points to 12,124.06, led by declines in the mining sector, while the Canadian dollar gained 0.08 of a cent to 99.89 cents US.

Also, home improvement chain Rona Inc. (TSX:RON) was in focus. A fund manager that owns about one-tenth of the company, Invesco Canada, is calling for shareholders to remove the company's board and install new directors.

U.S. indexes were higher as Cisco Systems Inc. shares surged almost eight per cent after the world's largest maker of computer networking gear said that its earnings rose 18 per cent in the latest quarter to US$2.1 billion or 39 cents a share.

The Dow Jones industrials gained 15.67 points to 12,771.85, the Nasdaq rose 15.44 points to 2,899.33 and the S&P 500 was up 2.84 at 1,377.37.

Oil rose six cents to US$85.44 a barrel.