The network, dismantled in an operation on 10 October, is accused of scamming thousands across Europe out of nearly €5 million.
Latvian police have busted a major internet fraud network that has scammed thousands of victims across Europe.
Police arrested seven suspects, the EU's law enforcement agency Europol said on Friday.
To dismantle the criminal ring, law enforcement investigators from Austria, Estonia and Latvia, in partnership with the EU agencies Europol and Eurojust, teamed up.
The probe culminated in an operation that took place on 10 October.
The detained suspects are believed to be responsible for more than 1,700 individual cyberfraud cases in Austria and 1,500 in Latvia.
They are accused of having scammed victims out of nearly €5 million, of which €4.5 million were in Austria and €420,000 in Latvia.
As part of the operation, which was dubbed SIMCARTEL, police seized 1,200 SIM box devices and 40,000 active SIM cards, Europol said.
"Other offences facilitated by this criminal service include fraud, extortion, migrant smuggling and the distribution of child sexual abuse material," Europol wrote in a statement.
In footage released by authorities, Latvia's State Police Counterterrorism Unit OMEGA could be seen smashing the doors of a building during the takedown operation.