The articles in the Oklahoman and the Kansas City Business Journal seem fairly innocuous: As a cost-cutting measure, Sprint plans to rely more on roaming for rural areas in the two states.

But the news prompted an attack from the head of AT&T's federal regulatory team, Bob Quinn.

In a pointed blog post published Monday afternoon, Quinn went after Sprint's decision to depend on other operators' networks to provide its customers with service in less-populated areas.

Characterizing the move as "massive Sprint disinvestment," Quinn criticized Sprint for using "other people's investments" instead of its own and skewered the FCC for making it easier for operators to roam on other company's networks.

"The FCC intervened in the competitive wireless market to ensure that Sprint doesn't have to invest in order to fill out its footprint," Quinn said, referring to a 2010 order that allowed an operator to get roaming, even in markets where they owned spectrum, and regulations passed in April 2011, which mandated that wireless operators agree to reasonable data roaming arrangements with their competitors. AT&T opposed both orders.

"Mind you, someone has to actually do the investing to make this possible, but thanks to the FCC's orders, it doesn't have to be Sprint that does that investing," Quinn said.

Sprint public affairs chief John Taylor rebutted Quinn's statement, saying that it actually doubled the amount of money it invested in its network last year.

"It's disappointing, but not surprising, that AT&T wants to challenge a consumer's right to access email, the Internet and other mobile broadband services wherever they may travel in the U.S.," Taylor said in an email response.

AT&T and Verizon Wireless were the only two U.S. wireless operators to oppose the FCC's data roaming order last spring.

"Sprint, as part of its Network Vision program, doubled its 2011 capital investment over 2010 to make tens of thousands of capacity upgrades," Taylor said.

The cash went toward Sprint's Network Vision project, which involves phasing out its iDEN network for a CDMA-based push-to-talk service, installing multi-mode base stations and rolling out LTE. Depending on other operators for service in less-profitable rural areas will allow Sprint to conserve cash to fund its infrastructure overhaul, estimated to cost between $4 billion and $5 billion.

AT&T isn't exactly feeling friendly these days to the institutions that opposed its doomed bid to buy T-Mobile USA, a failure that cost it $3 billion in cash and a chunk of its precious spectrum assets. The printed missive against Sprint – which was a high-profile opponent to the T-Mobile deal – comes on the heels of a blog post that harangued the FCC for its handling of spectrum auctions. The FCC's decision to refer the T-Mobile transaction to an administrative law judge was one of the final nails in the coffin for the troubled acquisition.

The Jan. 17 blog, also authored by Quinn, criticized the FCC for doing "some creative tinkering with auctions in the past, with dubious results." Quinn cited spectrum sold to so-called Designated Entities – which laid fallow when the companies went bankrupt – conditions on C-block and D-block 700 MHz spectrum, a clause in LightSquared's waiver that inhibited its ability to sign up AT&T or Verizon as customers, and how the agency handled its review of AT&T's purchase of 700 MHz spectrum once used for Qualcomm's Flo TV mobile television service.

On Jan. 13, AT&T legislative affairs executive Jim Cicconi said the company was "troubled" that the FCC disagreed with proposed legislation that would limit its ability to impose conditions on spectrum auctions.

"In our experience, anytime a regulatory agency seeks unfettered discretion, that is the best reason Congress should not give it to them," Cicconi wrote. The FCC later responded, setting off a short-lived tit-for-tat between the agency and AT&T.