Shares of Research In Motion Ltd fell more than 15 percent in pre-market trade on Friday, a day after the Blackberry maker posted weak quarterly results and outlook, prompting two analysts to downgrade the stock and several others to cut their price targets.

RIM on Thursday reported lower quarterly profit and its revenue missed its own limp forecast, forcing the company to slash its forecast.

Facing intense pressure from Apple Inc and Google Inc in the smartphone market, RIM also warned that its latest models would not hit U.S. stores until well into the valuable back-to-school shopping season.

The delay in new smartphone launches and RIM's inability to gain market share from the struggling mobile-phone giant Nokia Oyj drove Citigroup to downgrade the stock to sell from hold.

Citigroup analysts said RIM is missing the back-to-school season in North America due to a lack of compelling new products setting up risk of loss of consumer mindshare.

Bottom line, we believe RIM has no short-term fixes to improve product portfolio, brand perception, to reinvigorate share gains, revenue growth and profitability, Citigroup analysts wrote in a note to clients.

RIM has promised smartphones next year running on its new QNX platform, now featured in the PlayBook, but only after it releases a series of devices with an upgraded version of the current operating system.

While RIM's QNX-based handsets may be more competitive, we just don't know since the products remain 'vaporware' with no roadmap or launch dates revealed, National Bank Financial analysts, including Kris Thompson, said.

We expect competition and the QNX-based phone launches to pressure margins even lower, they said.

Apple's upcoming iPhone 5 slated to launch in the second half of the year is further expected to pressure RIM's North American business.

Analysts at National Bank, CIBC World Markets, Evercore Partners, ThinkEquity, BMO, UBS, Citigroup, Jefferies & Co and Susquehanna have lowered their price targets on RIM shares.

Evercore also downgraded the stock to equal weight.

RIM's US-listed shares fell $5.43 to $29.90 in pre-market trade on Friday. They closed at $35.33 on Thursday on Nasdaq.

RIM shares closed at C$34.37 on the Toronto Stock Exchange.

(Reporting by Soham Chatterjee and Tenzin Pema in Bangalore; Editing by Don Sebastian)