Facebook and Instagram parent company Meta Platforms is urging users to stay vigilant about “romance scams” ahead of Valentine’s Day, warning of unsolicited messages through its apps and other social media platforms, as well as general text messages.

Scammers tend to pose as “attractive, single and successful individuals,” Meta says. They often claim to have military, medical or business backgrounds, with photos either stolen from real people’s accounts or generated through artificial intelligence. Initially, messages are sent to a large pool of people in the hopes of getting a response. A scammer than builds trust over a period of time before they ask their target for money — either by claiming hardship or offering investment opportunities, usually in cryptocurrency.

Meta said it recently worked with research firm Graphika to take down romance scams in three common categories: those impersonating military officers, celebrity mimics and scammers posing as fake match-making agencies that target people in Africa — “claiming to offer opportunities to meet rich men from Western countries or build relationships with ‘African women.'”

In addition to taking down scam networks, Meta says it is testing other tools to combat bad actors, including facial recognition technology that compares suspicious users’ profile photos against a public figure’s image. But, for now, that only works for celebrity impersonations.

To stay vigilant, Meta recommend people be suspicious of messages from strangers. If you do engage, try to verify the person’s identity by looking them up on the platform — check when their accounts were created or use a reverse image search on their photos. Requests for money, whether in the form of gift cards or payment apps, should also be treated with skepticism.