Adding to positive sentiment, data showed the Canadian economy recorded better-than-expected growth, to an annualized 3.1 percent in the second quarter, from a downwardly revised 0.9 percent in the first quarter.

Energy shares led the way higher, alongside a rise in oil prices, as worries that the Ukraine crisis could trigger more sanctions lifted the commodity.

The resource-heavy benchmark TSX recovered from weakness early in the day to finish up for both the third week and month in a row. The index is up about 14 percent this year.

"It's a nice way to cap the summer," said Elvis Picardo, strategist and vice president of research at Global Securities in Vancouver. "Sentiment is robust, but investors are nervous about the upsurge in geopolitical risk," he added.

"We could be in for a period where the market trades sideways and investors digest these gains. Investors are bracing themselves for a higher degree of volatility as volumes return to normal levels next week."

The Toronto Stock Exchange's S&P/TSX composite index <.GSPTSE> rose 67.56 points, or 0.43 percent, to 15,625.73. Seven of the 10 main sectors on the index were higher.

The index gained 1.9 percent for August and 0.6 percent for the week.

In addition to concerns about tensions between Ukraine and Russia as Ukraine called for full NATO membership, Britain raised its terrorism alert to its second-highest level

Matt Skipp, president of SW8 Asset Management, said investors did not seem to be taking concerns about tensions around the world seriously enough.

"The consensus trade seems to be, 'I can buy equities with immunity because the economy is improving and rates are staying depressed,'" he said. "I would argue that you're at risk of a geopolitical event, whether it is Ukraine or the Middle East, that could have dire consequences for the global economy."

Financials, the index's most heavily weighted sector, rose 0.3 percent, with Bank of Montreal (>> Bank of Montreal) up 0.8 percent at C$83.66, and Bank of Nova Scotia (>> The Bank of Nova Scotia) rising 0.5 percent to C$72.04.

Canadian Natural Resources (>> Canadian Natural Resources Limited) provided the index with the biggest lift, up 1.4 percent at C$47.39, followed by Suncor Energy (>> Suncor Energy Inc.), which rose 1 percent to C$44.63.

Athabasca Oil Corp (>> Athabasca Oil Corp) jumped 4.4 percent to C$7.92 after it said it had closed the sale of its 40 percent interest in the Dover oil sands project.

(Editing by Tom Brown)

By John Tilak and Leah Schnurr