Twitter has permanently banned prominent anti-Trump brothers Brian and Ed Krassenstein, alleging that two of the biggest stars of #Resistance Twitter had broken the site’s rules about operating fake accounts and purchasing fake interactions with their accounts.

“The Twitter Rules apply to everyone,” a Twitter spokesperson said in a statement. “Operating multiple fake accounts and purchasing account interactions are strictly prohibited. Engaging in these behaviors will result in permanent suspension from the service.”

The suspensions are a major loss for the Krassensteins, who had used their massive Twitter followers and ability to quickly respond to tweets from Donald Trump to make themselves internet celebrities. Ed Krassenstein had roughly 925,000 followers before he was banned, while Brian Krassenstein had more than 697,000.

The brothers appeared to be unusually good at getting attention on Twitter. While the Twitter statement doesn’t explain what the Krassensteins allegedly did to illicitly promote their accounts, “fake interactions” could engage buying bots to retweet their posts, or buying fake followers to inflate their profiles on the site.

In a statement to The Daily Beast, the Krassensteins denied breaking Twitter rules.

“Twitter claims that we manipulated our interactions through the purchase of fake accounts and fake interactions,” the Krassenstein brothers said. “We have never once acquired anything for the purpose of increasing our Twitter presence.”

The Krassensteins say they only operated secondary accounts on Twitter to monitor death threats, as well as accounts for their businesses.

“None of those accounts were ever used for manipulative purposes as Twitter claims,” the Krassensteins said in the statement.

As heroes of the anti-Trump resistance, the Krassensteins won admiration from liberals and anger from conservatives for their willingness to tweak Trump and his supporters online. The Krassenstein brothers even turned their online fandom into a book—featuring a shirtless, muscular Special Counsel Robert Mueller pursuing Trump.

Before turning to politics in 2017, the brothers saw their homes raided by federal agents investigating an alleged investment scheme. The Krassensteins were not charged.