Bots appear to be spamming a US regulator's website over a proposed reversal of net neutrality rules, researchers have said.
According to three separate analyses, a flood of automated comments to the Federal Communications Commission (FCC) was detected over the weekend.
More than 400,000 comments with remarkably similar wording have been detected in recent days.
Net neutrality proponents argue that all internet traffic should be equal.
This means that no content provider should be able to, for example, charge more for faster access to certain data.
One expert described bot activity as a new form of protest.
"Someone has gone out of their way to make these seem like real submissions," wrote Chris Sinchok in a blog post about the apparently automated activity.
Having downloaded the comments and associated data, Mr Sinchok noticed that the names and email addresses associated with thousands of them also turned up in lists of personal data stolen from websites.
Using 'breached data'
He told the BBC that this suggested someone might be using information collected from breached databases to make the submissions look more authentic.
"It really seems like this is getting pooled from some place in an automated fashion and it's coming in at unreasonable rates," he said.
He added that the uniformity of the data was also a possible giveaway.
For example, many comments are essentially identical save for the occasional, small difference - such as the exact same sentence appearing in multiple comments, but with different letters capitalised each time.
And the rate at which comments were posted also seemed suspicious, starting and stopping in bursts, he added.
Earlier this month, the FCC said it had been targeted by a distributed denial of service (DDoS) attack that led to downtime for the comments system.
This followed a television appearance by comedian John Oliver in which he urged people to post comments against the proposals on the FCC's website.
"Net neutrality is such a hot-button issue and it's one of the few examples of online activism that's actually amounted to something," noted Prof Phil Howard at the Oxford Internet Institute.
He cited the 2014 online protests, after which President Obama stepped in to recommend that the FCC drop earlier proposals to curtail net neutrality.
"This is how people protest these days," said Prof Howard, referring to the apparently automated comments.
He also pointed out that a growing number of people had the necessary programming skills to do it.
However, Mr Sinchok is concerned that the bot activity will create the impression that genuine opposition to the FCC's current proposals does not really exist.
"There are people that care about this issue a lot," he told the BBC.
"Activity like this is really muddying the waters - and I don't want it to give [the FCC] an excuse to say, 'Hey, there's mixed support for this.'"
The FCC has not yet responded to a BBC request for comment.