A spokesperson for Sprint has revealed the carrier has turned on 4G LTE service in parts of San Francisco, New York City and Washington, DC. The company started flipping the switch in San Francisco about a month ago although coverage still remains spotty according to Engadget.

Sprint's Kelly Schlageter told The Verge that deployment is just beginning in San Francisco and that coverage is hard to describe because sites generally aren't contiguous. The spokesperson said there are some sites on air in and around San Francisco, kind of like popcorn. We are also told that other parts of New York State now have LTE service in addition to some cities in Florida like Jacksonville, Miami and Tampa.

Sprint announced 58 new areas of 4G LTE coverage late last month but the wireless provider is holding off on making any official announcements about expanded coverage until the infrastructure is built up enough to provide customers with a consistent level of service.

The slow, unannounced rollout is designed to let Sprint customers access the service in a few test areas. Schlageter said that rather than deploying a site, testing the equipment then turning it off until launch, they are leaving it on for customers to use wherever they find it.

Sprint recently said during an earnings call that they had fallen behind their initial rollout target for near-nationwide 4G LTE by the end of this year. The company now expects to hit this goal by early 2014, covering 250 million people when it's all said and done.