(Reuters) - The U.S. Immigration and Customs Enforcement agency (ICE) said will end its contract with BlackBerry maker Research In Motion in favor of Apple's iPhone, dealing a fresh blow to RIM just months ahead of its launch of a vital new device.The agency said in a solicitation document posted last week that it intends to buy iPhones for more than 17,600 employees - a purchase worth $2.1 million.The agency said it has relied on RIM for eight years but that RIM's technology "can no longer meet the mobile technology needs of the agency".It also said that it had analyzed Apple's iOS-based devices and Google's Android operating system and concluded