The US Secret Service disrupted a network of telecommunications devices that could have shut down cellular systems as leaders gather for the United Nations General Assembly in New York City.
The agency said on Tuesday that last month it found more than 300 SIM servers and 100,000 SIM cards that could have been used for telecom attacks within the area encompassing parts of New York, New Jersey and Connecticut.
"This network had the power to disable cell phone towers and essentially shut down the cellular network in New York City," said special agent in charge Matt McCool.
The devices were discovered within 35 miles (56km) of the UN, where leaders are meeting this week.
McCool said the "well-organised and well-funded" scheme involved "nation-state threat actors and individuals that are known to federal law enforcement".
