More than 800 suspected criminals have been arrested worldwide after being tricked into using an FBI-run encrypted messaging app, officials say.
The operation, jointly conceived by Australia and the FBI, saw devices with the ANOM app secretly distributed among criminals, allowing police to monitor their chats about drug smuggling, money laundering and even murder plots.
Officials called it a watershed moment.
Targets included drug gangs and people with links to the mafia.
Drugs, weapons, luxury vehicles and cash were also seized in the operation, which was conducted across more than a dozen countries. This included eight tonnes of cocaine, 250 guns and more than $48m (£34m) in various worldwide currencies and cryptocurrencies.
Australian Prime Minister Scott Morrison said the operation had "struck a heavy blow against organised crime" around the world.
European Union police agency Europol described Operation Trojan Shield/Greenlight as the "biggest ever law enforcement operation against encrypted communication".
Statements from law enforcement agencies did not name any of those arrested in the sting.
In Australia, 224 people were arrested including members of outlaw motorcycle gangs, mafia groups, Asian crime syndicates, and serious and organised crime groups.
Police said they also seized three tonnes of drugs and A$45m (£25m; $35m) in cash and assets, and acted on 20 "threats to kill", potentially saving the lives of a "significant number of innocent bystanders".
Mr Morrison said the sting, which was called Operation Ironside, was "a watershed moment in Australian law enforcement history".
New Zealand police said 35 people in the country had been arrested, and about NZ$3.7m (£1.9m, $2.7m) of assets seized.
"We believe the termination of these operations will have a significant impact on New Zealand's organised crime scene," National Organised Crime Group Director Detective Superintendent Greg Williams said.
In the US, the FBI unsealed an indictment against 17 people for distributing the ANOM-enabled devices - eight have so far been arrested, while the rest are on the run.
The FBI is expected to present more details later on Tuesday.
Europol's deputy executive director Jean-Philippe Lecouffe described the operation as an "exceptional success".
The agency did not break down the arrests in each country, but local officials said they included 70 people in Sweden and 49 in the Netherlands, according to Reuters news agency.
Linda Staaf, the Swedish police's head of intelligence, said the operation had helped to prevent more than 10 planned murders in Sweden.