Jim Tobin, senior vice-president for software and business services reporting directly to co-CEO Jim Balsillie, left the Canadian company months ago, RIM confirmed on Thursday in an email to Reuters.

The attrition comes as the smartphone maker struggles to regain its competitive edge against Apple Inc''s iPhone and iPad and a slew of devices using Google's Android software.

RIM has repeatedly delayed its new product releases, and once launched, some of its devices have received poor reviews. Earlier this month a global outage knocked out service for tens of millions of BlackBerry users across five continents.

In July RIM said it was slashing about 11 percent of its workforce because of falling sales and profit.