The government is violating the First Amendment by embarking on a "radical reinterpretation and expansion" of its power to punish broadcasters for indecent speech, a federal court was told Wednesday by FOX Television Stations Inc.

FOX, CBS Broadcasting Inc., NBC Universal Inc. and NBC Telemundo License Co. are suing the Federal Communications Commission, challenging the way the agency metes out punishment for airing shows that contain profanity. FOX filed formal arguments in a federal appeals court in New York. Later in the day, CBS and NBC also filed briefs.

The New York case is proceeding at the same time as a separate CBS challenge in a federal appeals court in Philadelphia, where the network is protesting an FCC fine over the partial disrobing of pop star Janet Jackson during a Super Bowl halftime show.

In contrast to the Jackson case, FOX is challenging what it calls an unprecedented campaign by federal regulators to punish broadcasters for airing "unintentional and isolated expletives" during broadcasts.

"The result is the end of truly live television and a gross expansion of the FCC's intrusion into the creative and editorial process," FOX argued in its court filing.

David Fiske, a spokesman for the FCC, released a statement saying: "By continuing to argue that it is OK to say the F-word and the S-word on television whenever it wants, Hollywood is demonstrating once again how out of touch it is with the American people. We believe there should be some limits on what can be shown on television when children are likely to be watching."

CBS said in a statement that what it is "seeking is a return to the FCC's previous time-honored practice of more measured indecency enforcement."

The case was sparked by a 76-page omnibus order by the FCC in March 2006 that settled "hundreds of thousands of complaints" regarding broadcast indecency. In the order, the FCC proposed fines against several broadcasts, but did not issue fines against four other shows that dealt with profane language.

Broadcasters sued. Earlier this month, the FCC dismissed complaints against the ABC program "NYPD Blue" on procedural grounds and reversed its finding on CBS' "The Early Show" because of its status as a news program. But the agency upheld its finding of indecency regarding two broadcasts of the Billboard Music Awards on FOX.

The FCC will have an opportunity to reply to the broadcasters in two weeks.

FOX Television is owned by News Corp., the parent company of FOX News Channel, which operates FOXNews.com.