Sept. 4 (Bloomberg) -- Comcast Corp., the second-biggest U.S. high-speed Internet service provider, asked a court to overturn a Federal Communications Commission ruling that it violated policies intended to keep the Internet open.

The FCC on Aug. 1 found Comcast had improperly blocked peer- to-peer programs such as BitTorrent that are used to share videos and other files, and told the company to stop. Comcast said it temporarily slowed some users' service when its network was congested.

``The commission's action was legally inappropriate and its findings were not justified by the record,'' Comcast Executive Vice President David Cohen said today in an e-mailed statement. Cohen said Comcast, the biggest U.S. cable-TV operator, still intends to ``comply fully'' with the FCC order.

Cable companies are wrestling with how to keep high-speed Internet services operating smoothly as demand soars for features such as streaming video that place heavy demands on networks.

Comcast said last month that it plans to slow the top Internet speed for its heaviest users, rather than target specific programs. Subscribers whose monthly Internet use exceeds 250 gigabytes of data, enough for 125 hours of standard- definition movies, may get a warning call and could lose their service.

Comcast filed the petition for review with the U.S. Court of Appeals for the D.C. Circuit in Washington.

`Disappointed'

``I'm certainly disappointed'' by the challenge, FCC Chairman Kevin Martin said in an interview. ``It was important for the commission to continue to protect consumers' unfettered access to the Internet.''

In filings with the FCC, Philadelphia-based Comcast had said that because there was no ``potentially applicable law,'' the agency couldn't issue a ruling about its network practices.

Martin said the commission ``definitely'' has the authority to act against Comcast.

Free Press and Public Knowledge, the Washington-based public interest groups that filed the complaint upon which the FCC acted, said they had anticipated Comcast's action.

``We believe the commission will prevail,'' Public Knowledge President Gigi Sohn said today in an e-mailed statement.

Comcast dropped 70 cents to $20.85 at 4 p.m. New York time in Nasdaq Stock Market trading. The shares have gained 14 percent this year.

AT&T Inc. is the biggest U.S. high-speed Internet service provider.

The case is Comcast Corp. v FCC, 08-1291, U.S. Circuit Court of Appeals, D.C. Circuit (Washington)

To contact the reporter on this story: Todd Shields in Washington at tshields3@bloomberg.net

Last Updated: September 4, 2008 16:51 EDT