The Secret Service announced Tuesday that it dismantled a network of electronic devices across five locations near New York City that could have been used to disrupt cellphone service and enable criminal activity.

Agents discovered more than 300 SIM servers and 100,000 SIM cards, along with cocaine, illegal firearms, and other equipment.

Officials said the network allowed anonymous, encrypted communications that were linked to assassination threats against senior U.S. officials.

While investigators have not found evidence of a specific plot to shut down New York’s cellphone system or the U.N. General Assembly, they warned the devices had the potential to disable cell towers and block emergency communications, NBC News has reported.

The Secret Service is still analyzing the recovered SIM cards to identify who built the network and whether it was intended to target world leaders visiting the city this week.