WhatsApp says it has taken down 6.8 million accounts linked to scammers targeting people around the world in the first half of this year.

Many were tied to scam centres run by organised criminals in South East Asia, who often used forced labour in their operations, the Meta-owned messaging platform says.

WhatsApp made the announcement as it rolled out new anti-scam measures to alert users to potential fraudulent activity, such as when a user is added to a group chat by someone not in their contacts list.

The crackdown targets an increasingly common tactic in which criminals hijack WhatsApp accounts or add users to group chats promoting fake investment schemes and other scams.

WhatsApp said that it "proactively detected and took down accounts before scam centres were able to operationalise them."