United States and Australian authorities hacked into an app used by criminals to read millions of encrypted messages, leading to hundreds of arrests of suspected organised crime figures in 18 countries, Australian officials said on Tuesday. “Operation Ironside” by Australian police and the US Federal Bureau of Investigation ensnared suspects in Australia, Asia, South America and the Middle East involved in the global narcotics trade, the officials said.

Australian Prime Minister Scott Morrison said the operation “struck a heavy blow against organised crime, not just in this country, but one that will echo around organised crime around the world.”

Australia said it had arrested 224 people, including members of outlawed motorcycle gangs, while New Zealand said it had detained 35 people.

The operation, which was conceived by Australian police and the FBI in 2018, saw officials in the US take control of the ANOM messaging app, which is popular with organised crime networks.

Executing Australia’s largest number of search warrants in one day, police on Monday seized 104 firearms as well as almost A$45 million ($34.9 million) in cash.

A total of 525 charges have already been laid but authorities expect more in the coming weeks.