The S&P/TSX composite index was 50.83 points lower to 12,653.9 as traders also took in data that showed the Canadian economy contracted in June.
The Canadian dollar closed up 0.01 of a cent to 94.97 cents US as geopolitical anxiety helped push the greenback higher against other currencies.
Statistics Canada reported that gross domestic product in June shrank by 0.5 per cent, which was in line with economists' expectations. At the same time, GDP grew at an annualized rate of 1.7 per cent, higher than the 1.6 per cent pace that was forecast.
Economists had expected the economy would hit a rough patch in June, largely because of severe flooding in Alberta and a construction sector strike in Quebec.
U.S. indexes racked up losses with traders reluctant to take on big positions ahead of a long weekend in the U.S. and Canada for the Labour Day holiday.
"It seems like the U.S. is determined to make a strike in absence of UN support and that will create a fair bit of uncertainty in the marketplace," said Philip Petursson, director of institutional equities at Manulife Asset Management.
"What is the best desirable outcome from this? And is it achievable? And I think perhaps the realization is, know what, even if we go in there the outcome isn’t better."
The Dow Jones industrials were down 30.64 points to 14,810.31, the Nasdaq lost 30.43 points to 3,589.87 and the S&P 500 index was 5.2 points lower to 1,632.97.
Markets have been rattled this week by the prospect of a U.S.-led punitive strike against Syria after an alleged chemical weapons attack.
The U.S. government said it has "high confidence" that Syria’s government carried out the attack Aug. 21, killing 1,429 people, including at least 426 children.
The UN has said their inspectors will wrap up their investigation Friday. Some of their experts will be travelling to laboratories in Europe to deliver the material they’ve collected this week in the Damascus suburbs purportedly hit by toxic gas.
Secretary of State John Kerry noted that UN investigators probing the chemical weapons attack are limited by a mandate to determine if an attack took place. He says they won’t say who is responsible.
In a surprise move, the British parliament voted late Thursday against military action in Syria, whittling down the core of the planned coalition.
The gold sector led decliners, down about 1.25 per cent as gold prices moved lower after spiking earlier in the week.
The December bullion contract on the Nymex fell $16.80 to US$1,396.10 an ounce. Barrick Gold Corp. (TSX:ABX) faded 58 cents to C$20.11.
The telecom sector was also a drag, giving back some of Thursday’s strong advance on speculation that U.S. telco Verizon won’t be entering the Canadian wireless market. Rogers Communications (TSX:RCI.B) lost 42 cents to $41.59.
The energy sector was down 0.7 per cent while the October crude contract on the New York Mercantile Exchange lost $1.15 to US$107.65 a barrel. Syria is not a major oil producer but a widening conflict there could affect major producers in the region or disrupt supply routes. Suncor Energy (TSX:SU) shed 60 cents to $35.50.
The base metals sector climbed per cent while December copper stepped back three cents to US$3.23 a pound. First Quantum Minerals (TSX:FM) climbed 59 cents to C$17.49.
Consumer staples ran up per cent with support from convenience store chain Alimentation Couche-Tard Inc. (TSX:ATD.B). Its shares ran up $3.38 or 5.89 per cent to $60.74 as it increased its quarterly dividend by 1.25 cents to 8.75 cents per share as it reported a first-quarter profit of $255 million or $1.35 per share. That was up from a profit of $102.9 million or 57 cents per share a year ago.
In other corporate news, Laurentian Bank (TSX:LB) reported third-quarter net income fell six per cent to $28.3 million, or 91 cents per share. Revenue grew 14 per cent to $221 million from $193.8 million and its shares slipped 62 cents to $44.33.
Bombardier Aerospace (TSX:BBD.B) said Friday it has received a flight test permit from Transport Canada for the first CSeries aircraft, clearing the way for the new jet's first flight. Its shares gained six cents to $4.79.