London (CNN)An encrypted messaging service used exclusively by criminals has been infiltrated by police in a major operation, leading to hundreds of arrests and the seizure of firearms, drugs and millions of dollars in cash.
Hundreds arrested after police infiltrate secret criminal phone network
EncroChat, which offered a secure mobile phone instant messaging service, was a "criminal marketplace" used by 60,000 people worldwide for coordinating the distribution of illicit goods, money laundering and plotting to kill rivals, according to the UK's National Crime Agency (NCA).
The NCA said it had made 746 arrests, and seized £54 million ($68 million) in cash, 77 firearms and more than two tons of drugs during the unprecedented Operation Venetic.
Police seized sub-machine guns, handguns, four grenades, an AK47 assault rifle and more than 1,800 rounds of ammunition during the operation, as well as more than 28 million Etizolam pills (street valium) from an illicit laboratory.
They also seized 55 high-value cars, and 73 luxury watches, the NCA said.
The crime agency said it had worked with police partners to prevent kidnappings and executions by "successfully mitigating over 200 threats to life."
UK Home Secretary Priti Patel tweeted that she had joined police in a dawn raid Thursday and congratulated the agency on its work.
"This operation demonstrates that criminals will not get away with using encrypted devices to plot vile crimes under the radar," she said in a statement.
Police in the Netherlands said they had made 60 arrests during their investigation, codenamed "Lemont," and had seized 25 tons of drugs, 20 million euros ($23 million), dozens of automatic weapons, 25 cars and expensive watches.
In a joint news conference with European law enforcement agencies, Dutch police said 19 synthetic drugs labs had been dismantled and more arrests were expected.
Operation Venetic -- the biggest-ever operation of its kind in the UK -- began in 2016, the NCA said, with international law enforcement agencies targeting EncroChat and sharing intelligence.
Two months ago, agencies in France and the Netherlands infiltrated the platform and shared the data via Europol, allowing police to monitor the private communications -- including photos and millions of messages -- of criminals.