The Cupertino-based company said it plans to release the next iPhone software update, containing many new features including the iTunes Wi-Fi Music Store, later this week.
"Apple strongly discourages users from installing unauthorized unlocking programs on their iPhones," the company wrote in a statement to the press. "Users who make unauthorized modifications to the software on their iPhone violate their iPhone software license agreement and void their warranty."
Apple added that the "permanent inability to use an iPhone due to installing unlocking software is not covered under the iPhone's warranty."
The iPhone maker's announcement reflects an increasingly consistent anti-modification policy from the company, which is likely the result of pressure from AT&T to enforce the multi-year exclusivity agreement between itself and Apple.
In one recent incident reported by Mac news site MacNN, a customer discovered that Apple had refused service on his iPhone at a company retail store and even suggested that the phone would be permanently blacklisted from further support regardless of how well it was restored to factory conditions.
Both moves are likely to put Apple's claims of possible permanent damage under close scrutiny, as the company will be responsible — if perhaps unintentionally — for breaking otherwise functional iPhones.
Update: TUAW offers a quick-and-dirty guide to relocking an iPhone.