Meta said Wednesday it had removed about 63,000 Instagram accounts in Nigeria that were engaging in sexual extortion and had taken down thousands of Facebook groups and pages that were trying to organize, recruit and train new scammers.

Sexual extortion, or sextortion , involves persuading someone to send explicit photos online and then threatening to make the images public if the victim does not pay money or obtain sexual favours .

Recent high-profile cases include two Nigerian brothers who pleaded guilty to sexually extorting teenage boys and young men in Michigan, one of whom committed suicide, and a Virginia deputy sheriff who sexually extorted and kidnapped a 15-year-old girl.

Sextortion cases have increased in recent years, particularly driven by a loosely organized group called the Yahoo Boys, which operates primarily out of Nigeria, Meta said. The company added that it had applied its policy on “dangerous organizations and individuals” to remove Facebook accounts and groups run by the group.

The deleted accounts were part of a “coordinated network” of about 2,500 accounts linked to a group of about 20 people who managed them, according to Meta.