The FCC this week said its electronic comment filing system was hit by a series of distributed denial-of-service attacks (DDos) Sunday that blocked legitimate commenters from sharing their thoughts with the commission.

According to FCC Chief Information Officer David Bray, the attacks began on Sunday night around midnight. But while the comment system remained live for the duration of the attacks, Bray indicated the DDoS activity overwhelmed the Commission’s servers and prevented them from responding to those trying to submit comments.

“These were deliberate attempts by external actors to bombard the FCC’s comment system with a high amount of traffic to our commercial cloud host. These actors were not attempting to file comments themselves; rather they made it difficult for legitimate commenters to access and file with the FCC,” Bray reported. “We have worked with our commercial partners to address this situation and will continue to monitor developments going forward.” 

The attacks occurred just after comedian John Oliver criticized FCC Chairman Ajit Pai’s recent proposal to roll back the Commission’s 2015 net neutrality rules in a new episode of his show “Last Week Tonight” on Sunday night. In the episode, Oliver urged viewers to share their thoughts on the proposal with the FCC using the comment filing system.

As of Tuesday morning, the proceeding had more than 130,000 comments.

Digital rights advocacy group Fight for the Future on Monday said the timing of the incident was cause for concern. The group indicated that either the FCC is being intentionally misleading about the nature of the surge in traffic – calling it a DDoS attack to cover for a system inadequately prepared to receive public comments – or some party actually carried out a DDoS attack to “actively prevent people from commenting in support of keeping the Title II net neutrality rules.”

“The FCC’s statement raises a lot of questions, and the agency should act immediately to ensure that voices of the public are not being silenced as it considers a move that would affect every single person that uses the internet,” the group noted in a statement. “Either of these scenarios should be concerning for anyone who cares about government transparency, free speech, and the future of the internet.”

Fight for the Future called for the FCC to release its logs for review by an independent security analyst or major news outlet to verify what happened Sunday night. The public “deserves to know” and the Commission “has a responsibility to maintain a functioning website and ensure that every member of the public who wants to submit a comment about net neutrality has the ability to do so,” the group said.