"I am a huge believer in the rule of law, but I also believe that no one in this country is beyond the law," Comey told reporters at FBI headquarters in Washington. "What concerns me about this is companies marketing something expressly to allow people to place themselves beyond the law."
Apple said last week that it would no longer be technically feasible to unlock encrypted iPhones and iPads for law enforcement because the devices would no longer allow user passcodes to be bypassed. The move comes as tech companies struggle to manage public concerns in the aftermath of last year's leak of classified National Security Agency documents about government access to private user data.
On a privacy site for its new mobile operating system, iOS 8, Apple outlined new features and tips for users on how to manage their privacy. It also included an explanation of how Apple will respond to government information requests in the future.
"Unlike our competitors, Apple cannot bypass your passcode and therefore cannot access this data," the company said. "So it's not technically feasible for us to respond to government warrants for the extraction of this data from devices in their possession running iOS 8."
Comey said that while he understood the need for privacy, government access to mobile devices may be needed in extreme circumstances, such as in the event of a terror attack.
"I like and believe very much that we should have to obtain a warrant from an independent judge to be able to take the content of anyone's closet or their smart phone," he said. "The notion that someone would market a closet that could never be opened -- even if it involves a case involving a child kidnapper and a court order -- to me does not make any sense."
Comey said FBI officials have had conversations with both Apple and Google about the marketing of their devices.
"Google is marketing their Android the same way: Buy our phone and law-enforcement, even with legal process, can never get access to it," he said.
"There will come a day -- well it comes every day in this business -- when it will matter a great, great deal to the lives of people of all kinds that we be able to with judicial authorization gain access to a kidnapper's or a terrorist or a criminal's device. I just want to make sure we have a good conversation in this country before that day comes. I'd hate to have people look at me and say, 'Well how come you can't save this kid,' 'how come you can't do this thing.'"
The director further expressed concern that public outcry over privacy in the wake of the NSA scandal may lead to unforeseen consequences.
"I get that the post-Snowden world has started an understandable pendulum swing," he said. "What I'm worried about is, this is an indication to us as a country and as a people that, boy, maybe that pendulum swung too far."
CORRECTION: This article has been edited to correct Comey's quote, "I am a huge believer in the rule of law, but I am also a believer that no one in this country is beyond the law." An earlier version wrongly quoted Comey as saying he's "a believer that no one in this country is above the law."