Research In Motion, maker of the BlackBerry smartphone, has missed third-quarter profit forecasts as consumers remain cautious in the economic downturn.

A strengthening US dollar has also eroded revenue at the Canadian company, which is due to release its results on 18 December. RIM flagged revenue down to $2.78 billion (£1.86 billion) in the quarter, against its forecast of up to $3.1 billion.

"Product launch timing, general economic conditions and foreign exchange volatility have tempered our results in the third quarter," co-chief executive Jim Balsillie said. RIM released its Bold and Storm models in the last quarter in an attempt to regain an advantage over Apple, which took the lead in smartphone shipments with the iPhone.

The company said US subscriber growth has gained momentum in the past few weeks.

Apple released a speedier version of the iPhone in July. To win more users away from the BlackBerry, Apple chief Steve Jobs added software that links the iPhone to corporate email systems, and opened an online applications store.