2025-03-18T21:53:56Z Read in app In this screengrab from a Marine Corps video on the dangers of cellphone usage, a Marine sends a message to his friends in battle. That has been deadly in Ukraine. Screenshot/US Marine Corps video This story is available exclusively to Business Insider subscribers. Become an Insider and start reading now.Have an account? The top Marine Corps general issued a warning to troops about battlefield cellphone usage.Cellphone data can reveal troop locations, making them vulnerable to enemy attacks.The war in Ukraine highlights the dangers of cellphone use in a combat environment.The Marine Corps' top general sent a video reminder out to the force this week, cautioning troops that battlefield cellphone usage can have deadly consequences. It points to Russian disasters in Ukraine.The video shared on social media shows a Marine who escaped enemy fire seeking refuge in an abandoned building. Assuming he's safe, the Marine pulls out his phone to send a text asking for assistance, sending his location with it.What no one realizes in this exchange is that the messages were intercepted. As his fellow Marines come to his aid, an enemy strike hits, resulting in fatalities.The video then turns the discussion to the conflict in Ukraine, noting news headlines from the war about the weaponization of mobile phones, and how cellphone usage by Russian soldiers led to a deadly Ukrainian strike. The video references a devastating strike that killed scores of Russian troops in Makiivka at the end of 2022. Moscow blamed cellphone usage, but there appear to have been multiple factors involved. It still serves as a point of caution all the same."If you can be sensed, you can be targeted," Gen. Eric Smith, Commandant of the Marine Corps, said in the video. "And if you can be targeted, you can be killed."While the Marine in the video shares his exact location, map coordinates are not needed for troops to endanger themselves or their comrades. When Russia launched its full-scale invasion of Ukraine, Russian troops posted videos on social media and called loved ones back home, all data that Ukraine used to strike.Phone calls, texts, and photos shared with friends over unprotected lines can be intercepted and mined for metadata, showing where they were taken. Open-source information gleaned from photos has been fatal in Ukraine.Russia has implemented several cellphone bans, and in 2024, Russia's lower house of parliament proposed legislation that would punish troops for using their personal phones in battle.It's not just phone usage that causes problems in combat; it's unintentional signal emissions, too, like the phones pinging off cell towers. "The character of war continues to change," Smith said. "The proliferation of technology has made signature management essential on the battlefield."The Marine Corps released its most current official policy on cell phones in 2024, Capt. Stephanie Baer, a spokesperson, told Business Insider.She said "the posted video is an amplification and continual reminder of the importance of the policy on usage in all situations," and added that the video's release was not linked to any specific recent events.The idea of "signature management" has been a critical tenant of discipline on the battlefield, but it's become increasingly important on modern battlefields where electronic emissions can betray positions and movements.A unit's "signature" generally refers to its presence and how easily it can be detected. Light, noise levels, and movement can all be elements of signature management. But with the proliferation of cell phones, and social media, the idea of signature discipline is morphing into a more urgent concern.Smith isn't the first Marine leader to warn about cellphones. Former Commandant Gen. David Berger noted such concerns about cellphone vulnerabilities to defense reporters in 2022."We have to be distributed. You have to have enough mobility that you can relocate your unit pretty often," he said of efforts to prepare for expeditionary operations throughout the Pacific. "You have to learn all about like some of us learned 30 years ago camouflage, decoys, deception," he said."What we didn't worry so much about 30 years ago now is every time you press a button, you're emitting," he said.