People have used app ratings to object to company policies in the past, but an ongoing campaign may be doing significant damage. NBC News has learned that pro-Palestinian activists are succeeding in a campaign to trash Facebook’s ratings in the Apple App Store and Google Play Store through “thousands” of one-star reviews. Many of the participants have accused Facebook of silencing Palestinians as they speak out about the recent escalation of violence with Israel.

The social network is taking the campaign very seriously, according to message board info NBC obtained. It’s marked as a “severity 1” issue, or just below a full-fledged site outage. A senior Facebook engineer reportedly said that users felt they were “censored” and otherwise suppressed.

Notably, though, the store operators weren’t necessarily intervening. A Facebook employee claimed that Apple declined to pull the one-star reviews. It’s not clear how Google has responded.

We’ve asked Apple and Google for comment. Facebook rejected accusations of censorship in a statement to NBC, claiming that its policies provide “everyone a voice” and that it applied them irrespective of beliefs. Spokesperson Andy Stone pointed to a team that was “closely monitoring” the Israeli-Palestinian situation to both pull harmful content and correct enforcement mistakes.

This won’t necessarily lead Facebook to change its approach. However, it’s notable that the campaign is having an effect in the first place — and that app store hosts might be staying out of the fray. It wouldn’t be surprising if more campaigns like this emerge in the future, even if they don’t ultimately lead to company action.