Qwest's claim in television, online, and newspaper advertisements that its Internet service is as fast or faster than Comcast is being challenged in court by the cable and broadband provider.

Qwest's company headquarters in Denver, Colorado.

Philadelphia-based Comcast , the nation's largest cable company, said Denver-based Qwest is engaging in false advertising with its claim based on a survey. A lawsuit filed Monday asked a judge to block Qwest from making the claim and also seeks "corrective" advertisements.