Research in Motion (RIM), maker of the BlackBerry mobile email device, has warned that it will not hit third-quarter and fourth-quarter subscriber targets because of delays in launching new devices.

RIM now expects third-quarter subscriber additions to be eight per cent lower than its previous forecast of 680,000 to 710,000. The company is still predicting quarterly revenue of between £461m and £487m.

For the fourth quarter, RIM expects subscriber additions of three per cent lower than its previous forecast of 775,000 to 825,000. It sees no change in its quarterly sales forecast of £404m to £529m.

RIM is also facing a possible injunction after US-based patent holding company NTP successfully sued in 2002 for patent infringement and won an injunction in 2003, stayed pending appeal, to shut down RIM's service in the US.

This marks the third consecutive quarter of disappointing subscriber growth for RIM, which is facing stronger competition from a wide range of operators and handset vendors.

The company blamed unexpected launch delays of its BlackBerry 8700 and 7130 series from early November to early December.

RIM claimed that its subscriber base grew about 17 per cent in the current quarter to more than four million, up from 3.65 million in September.