(REUTERS) - Sprint Nextel posted a wider fourth-quarter loss as costs from the Apple Inc. iPhone weighed down the No. 3 U.S. mobile operator.

The iPhone helped Sprint add 161,000 total net subscribers in the quarter, but this was behind the average expectation for 272,000 additions from eight analyst estimates compiled by Reuters. The company said it had sold 1.8 million iPhones in the quarter, 40 percent of which were to new customers joining its service.

Sprint's loss widened to $1.3 billion, or 43 cents per share, from $929 million, or 31 cents per share, a year earlier.

Revenue rose to $8.72 billion from $8.3 billion and was slightly ahead of Wall Street expectations for $8.69 billion, according to Thomson Reuters I/B/E/S.

(Reporting by Sinead Carew)