Research In Motion's stock fell as much as 5.2 per cent today as the company acknowledged a fresh round of layoffs has begun.

Shares closed down 47 cents, or 4.3 per cent, to $10.49 on the Toronto Stock Exchange. Earlier, they were down as much as 57 cents.

The Waterloo, Ont., maker of BlackBerry smartphones said Wednesday in a statement to various media outlets that it "has reduced some positions" as part of its plan to cut $1 billion in operating costs.

It is the first official acknowledgment from the company that it has begun a new round of job cuts.

The layoffs have been expected since CEO Thorsten Heins said last month that an unspecified number of positions will be eliminated as the company aims to slash expenses.

Sources told the Reuters news agency at the time that beleaguered RIM had already started slowly letting junior staff go, in a series of layoffs known among employees as "Goodbye Thursdays."

The Reuters report cited a source close to the company as saying as many as 6,000 workers could be affected, though other reports have pegged the number at 2,000.

RIM currently has about 16,500 employees worldwide, after letting go of 2,000 last summer.

The company's next financial update is scheduled for June 28, when it could provide details on the number and location of staff reductions.

BlackBerry has hemorrhaged market share to Apple's iPhone and devices running Google's Android operating system.

RIM stock is down more than 30 per cent this year, and way off its all-time high of $150.30.