The S&P/TSX composite index slipped 17.48 points to 14,227.66, led by losses in the financials sector.
The Canadian dollar was down 0.34 of a cent to 90.13 cents US.
New York indexes were also lower as the latest reading on consumer sentiment also weighed on stock prices. The University of Michigan's widely watched index declined to 79.9 from 81.6 in February and was lower than the 82.5 reading that had been forecast.
The Dow Jones industrials gave back 43.22 points to 16,065.67, the Nasdaq lost 15.02 points to 4,245.4 and the S&P 500 index slipped 5.21 points to 1,841.13.
Investors looked ahead to a referendum being held in the Crimea region of Ukraine on Sunday where residents will vote on whether they want to join Russia. The vote is being held two weeks after Russian troops initially moved into Crimea, where Russia has a key naval base and many of the people are Russian speaking.
If Crimea votes to secede, the U.S. and European Union plan to slap sanctions on Russian officials and businesses accused of escalating the crisis and undermining Ukraine’s new government.
"It’s not the results of the referendum that are the issue here — it’s the reaction from both Russia and the G7 nations afterwards," said Jean-Francois Dion, a portfolio adviser at RBC Wealth Management.
"What really matters is whether or not we do get sanctions and the secondary issue would be the smaller risk of some kind of debt restructuring for Ukraine or the urgent need of capital in the banking system if these tensions last too long."
Adding to nervousness was a warning from Russia that it reserves the right to intervene in defence of ethnic Russians it says are under threat in eastern Ukraine.
Meanwhile, China's growth prospects have also depressed markets this week in the wake of soft export, retail and industrial production numbers.
The TSX base metals segment has plunged about 11 per cent this week while copper, viewed as an economic proxy, has dropped almost 10 per cent over the last five sessions. Copper is also used for financing in China and last week's first-ever corporate default raised worries that other failed companies could dump large quantities of the metal on markets, further depressing prices.
The base metals component was slightly lower Friday as May copper rose three cents to US$2.95 an ounce.
The TSX financial sector was the major decliner, down 0.63 per cent.
Royal Bank (TSX:RY) is among 16 major banks being sued by the U.S. Federal Deposit Insurance Corporation. The lawsuit, filed in the federal district court in New York, was the latest to accuse financial institutions of conspiring to manipulate the influential Libor interest rate. Royal Bank shares declined 64 cents to $71.17.
The energy sector was up 0.17 per cent with April crude in New York up 69 cents to US$98.89 a barrel.
Traders opted for safety, sending gold higher for a fifth session with the April contract up $6.60 to US$1,379 an ounce for a gain of three per cent this week. The gold sector led advancers, up about one per cent on Friday.
The TSX shed 0.7 per cent for the week as a whole, with base metal losses balanced somewhat by a gain of about five per cent in the gold sector. The Dow industrials fell heavily, losing 2.35 per cent on the week.