AT&T Inc's quarterly revenue missed estimates on lower equipment sales, the company said on Tuesday, as customers held onto their phones longer and it lost wireless subscribers who pay a monthly bill.

The No. 2 U.S. wireless carrier had 61,000 fewer postpaid subscribers, who pay bills monthly, in North America on a net basis in the first quarter ended March 31.

Analysts on average had estimated 95,000 subscriber additions, according financial data and analytics firm FactSet.

AT&T's total operating revenue fell nearly three per cent to US$39.37 billion, mainly due to record-low sales of wireless handset sales.

Net income attributable to AT&T was US$3.47 billion, or 56 cents US a share, down from US$3.80 billion, or 61 cents US a share, in the year-ago period.

Excluding items, earnings per share matched analysts' consensus estimate of 74 cents US according to Thomson Reuters I/B/E/S. Revenue was expected at US$40.53 billion.

The company, which is in the process of acquiring Time Warner Inc, also said it would no longer give a full-year revenue forecast due to the unpredictability of wireless handset sales.