LAS VEGAS (AP)  The Federal Communications Commission will investigate complaints that Comcast actively interferes with Internet traffic as its subscribers try to share files online, the commission’s chairman, Kevin J. Martin, said Tuesday.

Mr. Martin confirmed the investigation in comments at the Consumer Electronics Show.

In an investigation last year, The Associated Press found that Comcast in some cases hindered file sharing by subscribers who used BitTorrent, a popular file-sharing program. The findings, first reported Oct. 19, confirmed claims by users who also noticed interference with other file-sharing applications.

“We look forward to responding to any F.C.C. inquiries regarding our broadband network management,” said David L. Cohen, executive vice president at Comcast.

Comcast denies that it blocks file sharing, but acknowledged after The A.P. article that it was “delaying” some traffic between computers that share files. The company said the intervention was necessary to improve the surfing experience for the majority of its subscribers.