Chicago and Los Angeles are in the running for Google Fiber deployments, with officials in both cities talking to Google about whether network construction is feasible.

"Home to a combined 6+ million people, Chicago and LA are the two largest metros we’ve engaged with to date," Google said in an announcement today.

Google Fiber is available in just three metro areas: Kansas City in Missouri and Kansas; Austin, Texas; and Provo, Utah. With the addition of Chicago and LA to the list of potential fiber cities, there are now 17 metro areas that have a good chance of getting Google's $70-per-month gigabit Internet service.

Among those 17, Google has said it will definitely build in six. The remaining 11, including Chicago and LA, have some work to do before Google will promise anything.

"As we kick off our usual checklist process, we’ll work closely with city leaders to collect detailed information about each metro area," Google's announcement said. "From Venice Beach to Wrigley Field, we’ll study the different factors that would affect construction—like city infrastructure and topography—and use that information to help us prepare to build a local fiber network. While we can’t guarantee that we’ll be able to bring Fiber to Chicago and LA, this is a big step for these cities and their leaders."

Google Fiber is not expanding as fast as AT&T's GigaPower fiber service. AT&T yesterday launched its gigabit service in parts of Los Angeles and West Palm Beach and had already made it available in Chicago. GigaPower is available in 20 metro areas nationwide.

AT&T has announced another 36 metro areas will get GigaPower later on and plans to make it available to more than 14 million homes and small businesses within four years. Neither AT&T nor Google have said how many homes and businesses can purchase their fiber services today.