Demand for the new Apple Inc. iPhone 5 has been "incredible," AT&T Inc Chief Executive Randall Stephenson said on Wednesday.

AT&T has seen a lot of anecdotal evidence of customers looking to buy the new smartphone even if they are not yet eligible for a subsidized upgrade, Stephenson said during a webcast of an investor conference.

He said AT&T would have more concrete details on demand after the first few weeks of sales.

The executive stood by AT&T's target to sell about 25 million smartphones this year, in line with 2011 sales. He also said the company was seeing strong demand for new wireless data plans launched in August.