Comcast Corp. is appealing an FCC ruling that the company is improperly blocking customers' Web traffic, triggering a legal battle that could determine the extent of the government's authority to regulate the Internet.

In a precedent-setting move, a divided Federal Communications Commission last month determined that the company is violating a federal policy that guarantees unfettered access to the Internet.

Comcast challenged the FCC decision Thursday in the U.S. District Court of Appeals in Washington.

Comcast executive vice president David L. Cohen said in a statement that the company is seeking "review and reversal" of the FCC order and that the commission's action was "legally inappropriate and its findings were not justified by the record."

The Comcast case arose from complaints by users of a type of "file-sharing" software often used to download large data files, usually video.

Tests by The Associated Press and others found that file-sharing transmissions were aborting prematurely. It was later discovered that the company was cutting off transfers without informing customers.