Canadian smartphone maker BlackBerry said it would lay off 4,500 employees, or more than a third of its workforce, and warned of a third-quarter net operating loss of up to $995 million.

The company's shares plunged Friday after the announcement and closed down more than 17 percent at $8.73 a share on the Nasdaq.

The layoffs are part of BlackBerry's goal of reducing its operating expenditures by the end of the first quarter of fiscal year 2015 by approximately 50 percent, the company said Friday in a financial release.

The Canadian company also said it expected to post $1.6 billion of revenue in the second quarter of the current fiscal year, which ends in March 2014, after selling approximately 3.7 million smartphones during that period.

The company acknowledged poor sales results for the new model of smartphones on which it has bet its future success.

"As a consequence of the more intense competition the company is experiencing in its hardware business, it expects to report a primarily non-cash, pre-tax charge against inventory and supply commitments in the second quarter of approximately $930 million to $960 million, which is primarily attributable to BlackBerry Z10 devices," Blackberry said.

The company also announced a change in its business strategy, saying that it planned to "refocus our offering on our end-to-end solution of hardware, software and services for enterprises and the productive, professional end user."

"We are implementing the difficult, but necessary operational changes announced today to address our position in a maturing and more competitive industry, and to drive the company toward profitability," BlackBerry President and CEO Thorsten Heins was quoted as saying in the release. EFE