CALGARY, Alberta (Reuters) - Suncor Energy Inc (>> Suncor Energy Inc.), Canada's largest oil and gas company, on Wednesday reported a third-quarter loss due to unrealized foreign exchange losses and posted lower operating profits as the slump in global crude prices dragged on.

The company reported a net loss of C$376 million, or 26 Canadian cents per share, as a result of an after-tax unrealized FX loss of C$786 million ($595.91 million) on the revaluation of U.S. dollar denominated debt.

In the year-prior quarter net earnings were C$919 million, or 63 Canadian cents per share.

Suncor's operating profit, which excludes one-time items, fell to C$410 million, or 28 Canadian cents per share, in the third quarter, from C$1.306 billion, or 89 Canadian cents per share, in the year-ago period.

Suncor produced a total of 566,100 barrels of oil equivalent per day, up from 519,300 in the third quarter of 2014.

The Calgary-based company's operations are mainly based in the oil sands of northern Alberta, where thousands of oil and gas worker layoffs and producers slashing capital spending have helped drive down production costs over the last year.

Suncor produced 430,300 bpd from the oil sands in the third quarter of 2015, compared to 411,700 bpd a year earlier and cash operating costs per barrel for oil sands operations dropped to C$27 a barrel in the third quarter of 2015, down from C$31.10 a barrel.

Chief Executive Steve Williams said those were the lowest per barrel cash costs in eight years, a plus in the "current challenging crude oil pricing environment."

Earlier this month Suncor made a hostile takeover bid for Canadian Oil Sands (>> Canadian Oil Sands Ltd), the largest stakeholder in the Syncrude project in northern Alberta.

Suncor, which owns 12 percent of Syncrude, said its share of the project's production was 28,100 bpd in the third quarter of 2015, compared to 29,400 bpd in the prior year quarter, after a fire at the facility cut production.

"We have been disappointed with Syncrude's performance for some time now. The asset ran at only 67 percent of capacity during the third quarter, and about 70 percent so far this year, in stark contrast to Suncor's upgrading operations that have been consistently achieving above 90 percent reliability this year," Williams said.

Suncor updated its 2015 crude oil pricing, and now expects Brent to trade at US$55 a barrel from US$60 and U.S. crude to trade at US$50 a barrel from US$54 a barrel.

(Reporting by Nia Williams; Editing by Christian Plumb)

By Nia Williams

Stocks treated in this article : Canadian Oil Sands Ltd, Suncor Energy Inc.