Comcast is throttling more traffic than it has previously admitted, Federal Communications Commission Chairman Kevin Martin told a U.S. Senate panel April 22. Martin also told lawmakers it appears Comcast broadband customers are not free to access all content on the Internet, including the ability to fully use peer-to-peer networks.

Martin’s comments come after two FCC hearings on charges that the nation’s largest cable provider deliberately throttles P2P applications such as BitTorrent during peak network hours, a practice that Comcast admits to. Comcast says its policy not only falls within the FCC’s reasonable network management exception to the FCC’s network neutrality rules, but it is also “imperceptible to the customer.”

Martin refuted Comcast’s claims, telling the Senate Commerce Committee, “It does not appear that this technique [throttling] was used only to occasionally delay traffic at particular nodes suffering from network congestion at that time.” According to Martin, the testimony so far presented to the FCC indicates Comcast’s efforts at managing P2P traffic “is typically deployed over a wider geographic or system area and would therefore have impacted nodes within a system simultaneously.”

Comcast’s technology, Martin added, “blocks the uploads of at least a large portion of subscribers in that part of the network, regardless of the actual levels of congestion at that particular time.”

Martin also said he had no fix on when Comcast will actually stop using its current approach, although Comcast said it plans to move to a “content-agnostic” platform available for up to 20 percent of Comcast’s customers by the end of the year. One of the primary network neutrality complaints against Comcast is that it singles out one program over another.