The US Department of Homeland Security (DHS) issued a warning on Wednesday (June 18th) that the number of signal jammers from China has dramatically increased, posing a threat to public safety sectors such as civil aviation and law enforcement in the United States.
According to the announcement posted on the official website of the Department of Homeland Security, despite efforts by Chinese companies to evade US inspections, Customs and Border Protection (CBP) has still detected a large quantity of Chinese-manufactured signal jammers being smuggled into the country.
The announcement revealed that since 2021, the number of signal jammers seized by Customs and Border Protection has increased by approximately 830%.
Signal jammers can interfere with various radio frequency channels, posing a threat to accident rescue, emergency response, law enforcement, and critical infrastructure.
A spokesperson for the Department of Homeland Security stated: “Instances of undocumented immigrants using signal jammers to disrupt communication during police operations, bank robberies, home invasions, and other dangerous criminal activities have been reported nationwide.”
He added, “National security begins at America’s ports, and Customs and Border Protection will remain vigilant. As Chinese manufacturers continue to attempt smuggling signal jammers into the US, we will continue to intercept these tools of terrorism. President Trump and Secretary Noem are committed to safeguarding America’s critical infrastructure and law enforcement agencies.”
The Department of Homeland Security pointed out that in recent years, the illegal use of signal jammers within the US has become increasingly common. Illegal immigrants from South America have been disrupting local law enforcement communications during break-ins or bank robberies in states such as Florida, Illinois, Ohio, Pennsylvania, Texas, Vermont, and Virginia using jammers.
The announcement cited specific incidents, such as in February 2025, when law enforcement in Texas apprehended an illegal immigrant from Chile in possession of a signal jammer.
In December 2024, a criminal used a jammer during a theft case when authorities were responding.
Signal jammers work by transmitting radio waves of a certain frequency to block specific communication channels, disrupting the establishment or maintenance of connections for communication devices within a specific wireless frequency range.
Signal jammers can block cell phone calls, texts, emails; disrupt Wi-Fi connections; interfere with GPS device signals for accurate positioning; impede emergency responders in locating your precise location.
Federal laws in the US prohibit private importation, operation, marketing, or sale of any device that can interfere with communication, Global Positioning System (GPS), or radar signals.
According to an announcement from the US Federal Communications Commission in 2012, the use of cell phone jammers, GPS jammers, or any other type of jammers to intercept, block, or disrupt government-authorized licensed communication systems is illegal. Moreover, importing, advertising, selling, or transporting any jamming devices is also illegal.
The announcement by the US Federal Communications Commission also warned that the commission’s enforcement bureau will adopt a “zero-tolerance policy” towards such violations and impose severe penalties on any offenders.