AT&T's exclusive deal to sell the iPhone is still paying off. The largest US telco added 1.3 million net new wireless customers in the first quarter as its residential landline subscriber numbers fell yet again.

Overall, the company saw quarterly profit rise 22% to $3.46 billion thanks to significant growth in its wireless and enterprise services units.

The wireless division saw revenues of $11.8 billion in Q1, up 18.3% year-over-year, according to an AP report.

AT&T ended the quarter with 71.4 million wireless subscribers.