Aereo, the digital subscription service facing a legal challenge from broadcasters, on Tuesday announced that it was expanding into Columbus, Cincinnati, Indianapolis and San Antonio.

Broadcasters are challenging Aereo’s offering of digital streams of station signals, claiming that they are a violation of copyright law. Aereo contends that the streams are legal, with each subscriber assigned a dime-sized remote antenna.

The company has already launched in New York City, Boston, Atlanta, Salt Lake City, Miami, Houston and Dallas. Earlier this year, Aereo announced the expansion in 22 cities this year and in 2014.

Although broadcasters have so far been unsuccessful in stopping the service in Manhattan, they are challenging Aereo in other cities. Hearst is awaiting a ruling from a Boston federal judge on whether to issue a preliminary injunction against Aereo, although at a hearing last week the judge said that he was leaning against putting an immediate stop to Aereo. He said that he would issue a final ruling before the end of the month.

Launch dates for the four new cities are to be announced later this year, Aereo said.

Aereo CEO and founder Chet Kanojia announced the expansion at the Goldman Sachs Communacopia Conference in New York on Tuesday.

“The goal is to keep knocking these cities out,” he said at the conference.