THE HAGUE: French and Dutch police said on July 2 they had shut down an encrypted phone network used by organised crime groups across Europe for assassination attempts and major drug deals.

Police had made dozens of arrests after hacking the EncroChat network so they could read millions of messages "over the shoulders" of suspects, they told a press conference at the EU's judicial agency Eurojust in The Hague.

EncroChat - which sells custom encrypted phones - sent a message to users in June warning them to throw away the devices as its servers had been "seized illegally by government entities", they said.

The hacking of the phones allowed the "disruption of criminal activities including violent attacks, corruption, attempted murders and large-scale drug transports", Eurojust and the EU police agency Europol said in a joint statement.

"Certain messages indicated plans to commit imminent violent crimes and triggered immediate action."

Dutch police had busted 19 meth labs, seized thousands of kilos of crystal meth and cocaine, and arrested more than 100 people as a result of the hack, Andy Kraag, head of the police central investigations division, told the press conference.

Dutch media said two of the country's most wanted meth smugglers had been arrested as a result of the investigation.

The statement said the investigation "made it possible to intercept, share and analyse millions of messages that were exchanged between criminals to plan serious crimes.

"For an important part, these messages were read by law enforcement in real time, over the shoulder of the unsuspecting senders."

 - AFP