Google Fiber today announced it will begin exploring Chicago and Los Angeles as markets for its gigabit internet service.

Those two cities will join a list of other potential Google Fiber cities including Louisville, Oklahoma City, Phoenix, Portland, San Diego and Tampa.

Google Fiber is currently up and running in Kansas City, Austin and Provo, Utah; and Google has committed to launching its internet service in Atlanta, Charlotte, Nashville, Raleigh-Durham, Salt Lake City and San Antonio.

Google’s exploration of Chicago and Los Angeles as potential Fiber markets comes as the company says it’s refined the checklist process for determining if a market is a good fit for Fiber.

“While we can’t guarantee that we’ll be able to bring Fiber to Chicago and L.A., this is a big step for these cities and their leaders. Planning for a project of this size is a huge undertaking, but we’ll be sure to keep residents updated along the way,” Google wrote in a blog post.

The possibility of extending Google Fiber’s reach comes one day after AT&T announced it would be bringing its GigaPower service to another 38 markets. GigaPower has already launched in many of the same markets that Google Fiber is currently or considering deploying in, but AT&T is under more pressure to expand. A condition of AT&T’s merger with DirecTV dictated the carrier build out its fiber network to an additional 12.5 million customer locations.