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... In five locations within 35 miles of New York, Secret Service agents discovered more than 300 co-located SIM servers and 100,000 SIM cards, officials said. They said the system could also be used for criminal activity and that 80 grams of cocaine, illegal firearms, computers and cellphones were also found.

"These devices allowed anonymous, encrypted communications between potential threat actors and criminal enterprises, enabling criminal organizations to operate undetected," Matt McCool, the head of the Secret Service New York Field Office, said in a video statement released Tuesday morning. "This network had the potential to disable cellphone towers and essentially shut down the cellular network in New York City." ...

Another official, who spoke on the condition of anonymity, said that the networks could also be used to disable EMS and police communications, as well as for encrypted communications.

"This network can be used to disable cellphone towers. It can enable 'denial of service' attacks, which means, basically, they could block EMS or police from responding to a scene if needed," the official said. "They can also be used to do anonymous, encrypted communication." ...