Major North American markets experienced steep drops Friday following weeks of declines and volatility.

This week is "one for the history books," said James Robertson, senior portfolio manager at Manulife Asset Management Ltd. "Intraday volatility has been so extreme."

The S&P/TSX composite index retreated 141.87 points to 14,795.13 despite being in positive territory earlier in the day.

The index opened on positive employment data, he said.

Canada's unemployment rate last month was the lowest since Statistics Canada started measuring comparable data more than 40 years ago as the jobless rate fell to 5.6 per cent for November, according to the agency. The country also added 94,100 net jobs, which is the largest monthly increase since March 2012.

Energy stocks also helped boost the index early on as oil prices rose. The January crude contract rose US$1.12 to US$52.61 per barrel.

The commodity price increased on news that OPEC countries reached an agreement to reduce global oil production by 1.2 million barrels a day -- 800,000 by OPEC countries and 400,000 by Russia and other non-OPEC members -- for six months starting in January.

The energy sector finished the day on a positive note, but it wasn't enough to lift the TSX as the market tone deteriorated over the course of the day.

"The market always gets particularly nervous in that last hour of trading on a Friday when it's been a weak week," Robertson said.

The day before, the TSX closed at its lowest level in five weeks -- down nearly 246 points for the day.

In New York, markets also ended the day in the red. The Dow Jones industrial average plunged 558.72 points to 24,388.95. The S&P 500 index shed 62.87 points to 2,633.08 while the Nasdaq composite fell 219.01 points to 6,969.25.

Markets are concerned about growth, trade wars and geopolitical risk in Europe, among other things, Robertson said.

"The markets are responding as they typically would when there's a lot to worry about, which is that they're extremely unnerved and very volatile."

Still he expects that as long as the economy continues to perform reasonably well, investors will look back on this in six months as a buying opportunity.

The February gold contract gained US$9.00 to US$1,252.60 as the precious metal is considered by investors to be a safe haven during turbulent market times.

Elsewhere in commodities, the January natural gas contract increased 16 cents to roughly US$4.49 per mmBTU and the March copper contract advanced nearly two cents to about US$2.76 a pound.

With files from The Associated Press