This article has been updated to include comments from Mike Sievert, CMO for T-Mobile. 

AT&T lashed out at T-Mobile yesterday by taking out full-page ads in the New York Times, Wall Street Journal and USA Today. 

The ads appear to be in response to T-Mobile's outspoken new CEO, John Legere who has made it clear that he intends to engage AT&T head on as part of the company's "challenger" strategy. At this year's Consumer Electronics Show in Las Vegas, Legere went so far as to call AT&T's network "crap."

Mike Sievert, chief marketing officer for T-Mobile, said he was glad AT&T is paying attention. 

“Wow. Looks like we struck a chord. AT&T doth protest too much. Glad they’re spending their money to print our name," Sievert said in emailed comments.  

The ads from AT&T published yesterday claim that T-Mobile's network is only half as fast as AT&Ts and drops twice as many calls. At the bottom of the page is text that warns, "Don't be fooled by their misleading claims. For the better network experience count on AT&T." 

AT&T hasn't been put on the offensive to this extent since it sparred with Verizon Wireless over coverage maps used in its advertising. Consumers can expect to see more of this back and forth, as Legere targets the only other GSM carrier in the United States. T-Mobile has been able to bring quite a few AT&T iPhone users over to its network. 

T-Mobile's tough stance certainly shouldn't come as a surprise to AT&T. During remarks at parent company Deutsche Telekom's annual investor conference back in December, Legere was up front about how the carrier would proceed, as it awaits more spectrum through its proposed acquisition of MetroPCS. 

"You love your iPhone, but you hate AT&T. I want you to get used to that kind of tone, because that is the way we're going to play," Legere said.  

The heated rivalry between the two carriers comes after regulators thwarted a $40 billion acquisition of T-Mobile by AT&T, leaving both companies to pick up the pieces of what they thought should have been a done deal.