Telecom giant AT&T, currently the only provider for Apple's iPhones in the United States feared that it would not be able to bag exclusive contracts for Apple's iPhones forever.

Apple's iPhones have played a major role in luring customers away from rivals such as T-Mobile, Verizon Wireless and Sprint Nextel.

AT&T reported that the company had gained 1.2 million subscribers during the second quarter and approximately two-thirds got AT&T's service for their iPhones. To add to AT&T's concerns Apple supposedly desires to hit a deal with service provider Verizon.

On the other hand, Randall Stephenson, AT&T Chief Executive Officer, who was speaking at Fortune-sponsored conference said about the contract between two companies, "On balance, I think it works really, really well -- maybe as well as any strategic partnership we have."

But when took a glance of overall cellphone service in the U. S., Verizon stood at first position with 87.7 million customers and AT&T stood at second position with 79.6 million customers.

ComScore's fresh study revealed that AT&T had pocketed two-fold smartphone users when compared with other service providers.

AT&T's exclusive contract with Apple is expected to expire next year. However, AT&T is trying negotiations to get the contract extended.