A US TV channel has forced Twitter to remove tweets linking to a news story about pirated content – including tweets from free speech campaigners complaining that the social network was removing other people’s tweets.

Starz, the network that airs American Gods, The 100 and Knightfall in the US, sent the takedown requests after the copyright and privacy news site TorrentFreak reported on a leak of promotional copies of those TV shows and others. TorrentFreak’s story did not contain any links to the pirated material, although it did include four screenshots of the content in order to report the alleged source of the leak.

But when TorrentFreak tweeted a link to the news story, Starz sent Twitter a legal demand to remove the tweet, alleging it infringed the company’s copyright because it linked to a website depicting “images of unreleased episodes … and information about their illegal availability”.

TorrentFreak disputed the takedown request, arguing that “our article only includes a single identifiable frame from a leaked American Gods episode, to show the screener watermarks, which are central to the story. That’s just 0.001% of the episode in question, without audio, which is generally seen as fair use, especially in a news context.”

The Electronic Frontier Foundation, a US-based internet rights group, tweeted its support, noting that the article “is a far cry … from an infringement”. The media journalist Mathew Ingram also tweeted the news, calling it “disturbing”.

Both of those tweets were also removed after requests from Starz. Ingram sent another tweet criticising the removal of his tweet criticising the removal of TorrentFreaks’ tweet. That tweet was also removed after a request from Starz.

Under the US Digital Millennium Copyright Act (DMCA), copyright holders can file takedown requests to companies hosting user-generated content, informing them of infringement and requiring them to remove the content. If a user believes they have been wrongly censored, they can file a counter-claim, explaining why the content is not infringement, and requiring the host to restore it. The EFF says it has done so.

“DMCA claims can be intimidating, especially to people who don’t know the ins and outs of the process … we’ll keep calling out abusive takedowns and helping people defend their rights to speak on the internet,” the EFF said in a statement.

Twitter declined to comment. In a statement on Tuesday, Starz apologised for the takedowns, which it attributed to an overzealous third-party contractor. “It appears that in this case, some posts were inadvertently caught up in the sweep that may fall outside the DMCA guidelines,” the company said. “That was never our intention and we apologise to those who were incorrectly targeted. We are in the process of reviewing all of the impacted posts as well as the scope and procedure for the previous takedowns and are working with our vendors to reinstate any such content that was inappropriately targeted for removal.”

Using the DMCA takedown process to force content to be removed is a common issue on social media. In 2013, Straight Pride UK, a Russian front that supported homophobic laws in Britain, forced the blogging platform WordPress to remove an interview, eventually sparking a two-year court case.

Even legitimate takedown requests have proved controversial. Earlier this month, Warner Bros forced Twitter to remove a video posted by the US president, Donald Trump, which reused some music from a Batman film without permission. In a statement, Warner Bros said: “The use of Warner Bros’ score from The Dark Knight Rises in the campaign video was unauthorised. We are working through the appropriate legal channels to have it removed.”