After months of allegations that Comcast has been throttling BitTorrent uploads, a report from the Associated Press on Friday appears to verify the claim.

Accusations have been floating around the Internet for some time that Comcast, the nation's largest cable TV operator and the second-largest Internet service provider, engages in throttling peer-to-peer activity.

On Friday, however, the Associated Press said it had confirmed "through nationwide tests" that Comcast blocks some BitTorrent activity.

Comcast representatives avoided responding to the claim directly. At the Web 2.0 Summit in San Francisco on Friday, Comcast Interactive Media President Amy Banse responded to questions about P2P throttling by pointing to the company's need to "manage" heavy Internet use.

"99.9 percent of our customers happily say they use e-mail and are uploading and downloading video and photos every day at speeds they enjoy," she said. "There are .01 percent that are engaging in what we call 'excessive use.' We're talking about things like sending 18,000 e-mails every hour of every month. We need to manage that, and to the extent we identify this excessive use, we call those customers and offer them additional services like commercial services."

She later said if that .01 percent upgrade to the higher cost commercial services, "they could BitTorrent to their heart's content. (She didn't address the fact that sending 18,000 e-mails an hour may be a sign of a spam bot infection.)

Comcast did not respond to request for further comment by press time.

The company has been on record as supporting net neutrality. COO Stephen Burke told The Wall Street Journal last year that "right now, we’re going as fast as we can to make our services good for our customers on any site they go to, and we have no intention of changing that."

The AP's tests would seem to indicate otherwise. BitTorrent is a peer sharing technology that has each user on the node uploading and downloading at the same time. As they receive the bits of a file, they send it right back out to others who are downloading. The AP found that incomplete downloads are unaffected, but that Comcast meddles with the uploading of completed files.

The report claims that PCs uploading completed files are sent a message from Comcast that tells it to stop sending, which terminates the transfer. Both parties involved in the file transfer typically think the other is responsible for stopping the transfer.

In fairness to cable ISPs like Comcast, it can only allow so much uploading. Because typical cable Internet implementations involve far more downstream bandwidth than upstream, all of its option packages advertise faster download speeds than uploading.

Despite limitations on cable modem upstream bandwidth, AT&T CEO and chairman Randall Stephenson seized the opportunity at today's Web 2.0 conference to take a swipe at Comcast's alleged throttling.

"We don't do that," he said. "A lot of our bandwidth is dedicated to peer-to-peer. We don't block anyone's content."

BitTorrent did not respond to requests for comment from InternetNews.com by press time.

Even if Comcast isn't breaking any rules, the AP's findings may leave the cable giant with a black eye, said Ben Bajarin, digital media analyst for Creative Strategies.

"It's putting rules and regulations on how something free like the Internet can be used," he told InternetNews.com. "Even though BitTorrent is legitimate in a lot of things they are doing, what [Comcast's] moves show is if you want to upload files, you have to have their permission to do that. What if you are a legit content provider and want to do that?"

InternetNews.com's West Coast Bureau Chief Dave Needle contributed to this article.