Facebook has filed a lawsuit against two Asian app developers for running fraudulent advertising operations which exploited people’s devices.

Hong Kong-based LionMobi and Singapore-based JediMobi have been accused of ‘click injection’ fraud. It is claimed the pair created malicious apps and introduced them to the Google Play store to infect people’s phones. Once a user had installed one of the apps on their phone, the malware would generate fake user clicks on Facebook ads, giving the impression that ‘real’ people had clicked on the ads and tricking Facebook’s advertising network to pay out for those clicks.

“LionMobi and JediMobi generated unearned payouts from Facebook for misrepresenting that a real person had clicked on the ads,” said Jessica Romero, director of platform enforcement and litigation at Facebook, in a blog post. “The ads were part of Facebook’s Audience Network. LionMobi also advertised its malicious apps on Facebook, in violation of our Advertising Policies.”

Both LionMobi and JediMobi have been banned from the Facebook Audience Network and all affected advertisers have been refunded. Facebook did not announce how many users it believes were affected or how much money it may have paid out to the accused parties.