Two days after AT&T claimed it has to "pause" a 100-city fiber build because of uncertainty over network neutrality rules, the Federal Communications Commission today asked the company to finally detail its vague plans for fiber construction.

Despite making all sorts of bold promises about bringing fiber to customers and claiming its fiber construction is contingent on the government giving it what it wants, AT&T has never detailed its exact fiber plans. For one thing, AT&T never promised to build in all of the 100 cities and towns it named as potential fiber spots. The company would only build in cities and towns where local leaders gave AT&T whatever it wanted. In all likelihood, only a small portion of the 100 municipalities were likely to get fiber, and nobody knows which ones.

Yet this week, AT&T CEO Randall Stephenson made it sound as though a full 100 cities and towns would lose a fiber opportunity if the company doesn't like the FCC's final net neutrality proposal. "We can't go out and invest that kind of money deploying fiber to 100 cities not knowing under what rules those investments will be governed," he told investors Wednesday.

AT&T has separately claimed it will bring fiber-to-the-premises Internet service to "2 million additional locations" if it's allowed to buy DirecTV. But since AT&T never said how many locations it would bring fiber to if the merger is rejected, it's not clear what that 2 million number is in addition to. In short, no one outside of AT&T knows how extensive the company's fiber buildouts are planned to be.

Today, the FCC challenged AT&T to finally reveal some facts about its fiber plans in a letter to AT&T Senior VP Robert Quinn. Jamillia Ferris, a former Justice Department antitrust lawyer who joined the FCC to review the AT&T/DirecTV merger, began the letter by describing Stephenson's statement that "the Company would limit its fiber deployment to the '2 million additional homes' that are 'commitments to the DirecTV announcement' and that any other fiber deployment would depend on the outcome of the Commission’s Open Internet Proceeding." Ferris then asked Quinn for:

(a) Data regarding the Company’s current plans for fiber deployment, specifically: (1) the current number of households to which fiber is deployed and the breakdown by technology (i.e., FTTP [fiber-to-the-premises] or FTTN [fiber-to-the-node]) and geographic area of deployment; (2) the total number of households to which the Company planned to deploy fiber prior to the Company’s decision to limit deployment to the 2 million households and the breakdown by technology and geographic area of deployment; and (3) the total number of households to which the Company currently plans to deploy fiber, including the 2 million households, and the breakdown by technology and geographic area of deployment; (b) A description of (1) whether the AT&T FTTP Investment Model demonstrates that fiber deployment is now unprofitable; and (2) whether the fiber to the 2 million homes following acquisition of DirecTV would be unprofitable; and (c) All documents relating to the Company’s decision to limit AT&T’s deployment of fiber to 2 million homes following the acquisition of DirecTV.

Ferris asked Quinn for a response by November 21. AT&T told Re/code that it is “happy to respond to the questions posed by the FCC in its review of our merger with DirecTV. As we made clear earlier this week, we remain committed to our DirecTV merger-related build-out plans.”

The net neutrality debate went into overdrive this week when President Obama urged the FCC to reclassify broadband as a utility and prevent Internet providers from blocking or throttling content or charging websites for prioritization. FCC Chairman Tom Wheeler hasn't detailed his plans yet, but Internet service providers, Republican members of Congress, and Republican members of the FCC lined up in opposition.