TikTok isn't just for dance memes -- it's now being used by amateur investigators to track the Russian military buildup along Ukraine's borders.
Among those researchers is the Conflict Intelligence Team, or CIT, a tight-knit collection of investigators based between Russia and Ukraine.
CIT practices open-source intelligence, a method of gathering and analyzing information that, as its name suggests, draws on publicly available data like social media posts and satellite imagery.
"It's basically a bunch of independent bloggers slash researchers slash military equipment enthusiasts," said Kirill Mikhailov, one of a handful of the group's core members. Mikhailov, 33, is from Russia but currently lives in Kyiv, Ukraine.
The group came together in 2014, he said, during the early days of fighting in eastern Ukraine between that country's military and pro-Russian separatists. Mikhailov said the group's audience is primarily "people in Russia who need to be informed about this stuff," but the group's work is also translated into English for Western audiences.
MORE: Bomb shelters, guerrilla war: Building Ukraine's resistanceCIT's research has been cited widely in recent months, including in a January 15 analysis of Russia's military buildup near Ukraine by two experts from the nonprofit CNA, a think tank that advises the US military.
The group's work has also appeared in recent publications by the Atlantic Council's Digital Forensic Research Lab.
Thomas Bullock, an analyst at the private intelligence firm Jane's, pointed to CIT as one of the best outfits currently tracking Russia's military buildup.
Gathering data amid Russia-Ukraine tensions
The Biden administration has warned that Russia may fabricate a pretext to invade Ukraine, a charge Russia denies. The government of Ukrainian President Volodymyr Zelensky has downplayed the likelihood of a Russian invasion.
Amid this tension, which is spanning across the globe, Mikhailov explained one way how CIT gathers some of its data.
"Ideally, every train in Russia is logged in some central database," Mikhailov said.
A train's departure is checked against social media images -- certain Russian-language TikTok hashtags abound with videos of trains carrying multiple launch rocket systems, troop carriers, and tanks -- which researchers match visually to stations along the trains' routes.
The type of hardware on a train, Mikhailov said, can in some cases be matched to specific military formations. CIT and other researchers have spotted in social media videos equipment allegedly used by units of Russia's storied 76th Guards Air Assault paratrooper division, for example, due to the specific vehicles being used, their distinctive paint jobs, or unit markings.
This kind of information can be cross-referenced against the known home base of a military unit.
Researchers also supplement their findings with satellite data or, in some cases, social media comments.
"If a TikTok goes viral -- like, super viral -- then we can get lucky," Mikhailov said, as the videos attract comments from soldiers' relatives.
These comments can contain useful nuggets of information, Mikhailov said, like suggestions that a loved one's military deployment will be longer than the routine exercises publicly announced by Russia's military.
"There is no hiding" in today's global military landscape, according to Robert Abrams an ABC News contributor and the former commander of U.S. forces in Korea.
Open-source intelligence is more pervasive than ever now; everyone has a cellphone and satellite images are cheaper to obtain.
"From a military perspective, you have to really think through how you are going to protect your position and your movements and what your capabilities are," said Abrams. "You don't have to just worry about aircraft flying with side or forward looking infrared radar, you now have to worry about Joe Schmoe on the street corner with a cellphone."
Verifying gathered information
When the U.S. military makes decisions based on publicly available information -- the kind used by CIT -- that data is cross-referenced with other forms of intelligence, like human sources or intercepted communications, Abrams said.
"You don't make decisions and assessments on one report or one source of intelligence. As a general rule, you want to cross-cue with another form of intelligence," Abrams said.
To avoid disinformation, Mikhailov said CIT's researchers aim to collect social media posts from genuine eyewitnesses.
Satellite imagery also helps verify the data CIT collects, Mikhailov said.
But one method used by CIT of validating their findings has recently become trickier, after, Mikhailov said, an intervention by Russia's authorities.
Eight-digit numbers on the side of a train car can aid CIT in isolating a specific train and obtaining a history of its movements. That data is now harder to come by, Mikhailov said.
"They've been blocking our accounts, they've been limiting some specific types of requests, like you could request to see all trains that are currently at a station. It's not available at this point," Mikhailov said.
The most significant recent change, Mikhailov said, was the removal of data about journeys by trains carrying military cargo.
MORE: UN Security Council adjourns without action after US, Russia spar over UkraineThis wasn't the first time a new roadblock has been thrown up for open-source researchers. In 2019, Russian lawmakers approved a bill blocking troops there from using smartphones while on duty and from posting personal details online.
Mikhailov said researchers are adapting to the latest setbacks.
"We have found some workarounds and loopholes they haven't plugged yet," he said.