The FCC said that it was subject to “multiple distributed denial-of-service attacks” starting on Sunday night, hours after John Oliver called on viewers of his HBO series “Last Week Tonight” to file comments to urge the agency to preserve current net neutrality rules.

“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,” said David Bray, the FCC’s chief information officer. “These actors were not attempting to file comments themselves; rather they made it difficult for legitimate commenters to access and file with the FCC.”

He said that the attacks began at midnight. He did not say whether the attacks were in any way related to Oliver’s segment. An FCC spokesman, Mark Wigfield, said that the attacks ended about 8:45 a.m. this morning.

Oliver urged viewers to go to the FCC’s website to file comments, just as he did in 2014, when the FCC was deliberating its latest version of net neutrality rules.

Bray said that the comment system “remained up and running the entire time,” but that the attacks “tied up the servers and prevented them from responding to people attempting to submit comments.”

“We have worked with our commercial partners to address this situation and will continue to monitor developments going forward,” he said.

So far, there have been more than 100,000 filings on net neutrality since Sunday, the bulk of them since Oliver’s show, according to a reading of the FCC file. Oliver announced on the air that they had secured a URL — gofccyourself.com — to make it easier for users to find the proceeding and comment page.

FCC Chairman Ajit Pai has proposed repealing the FCC’s reclassification of internet service as a “Title II” common carrier. That was the regulatory maneuver the agency took in 2015 to impose a robust set of net neutrality rules.

Critics of Pai’s proposal say it would weaken the rules and diminish the agency’s authority.

Fight for the Future, a group that pushed for the 2015 net neutrality rules and is defending them now, said that the incident raises questions of just what happened.

“The FCC should immediately release its logs to an independent security analyst or major news outlet to verify exactly what happened last night,” said Evan Greer, the group’s campaign director. “The public deserves to know, and the FCC 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. Anything less is a subversion of our democracy.”