Russia's invasion of Ukraine has unleashed a flood of misleading and false material on TikTok. The popular app used by more than 1 billion people has been amplifying videos portraying old conflicts, scenes from movies and even video game battles as if showing on-the-ground live footage.

In times of crisis, social media platforms are always struggling to stay ahead of misinformation and make round-the-clock calls on when a viral post should be removed. But the flurry of conflict-themed footage now on TikTok has overwhelmed the platform in new ways, sending countless fake or videos framed as if depicting the war in Ukraine to millions of viewers.

"Though it's crucial that the public remain informed of such high-stakes situations, it seems that the platform's design is incompatible with the needs of the current moment," wrote independent researcher Abbie Richards who works with the liberal watchdog group Media Matters.

Frequent users of TikTok have taken notice, like Quinn Poseley, a 20-year-old student at the University of Southern California.

"I've seen videos that are from Crimea like from 2014 that are just old and they're acting like they're happening right now. I've seen photos and stuff that are just straight up Palestine," he said.

He added that when something looks fake on his TikTok feed, known as a "For You Page," he usually just moves past it fast and and goes on with life.

"You're getting 15 videos in 30 seconds," he said. "It's hard to stop and try to think about everything critically."

TikTok, which is owned by the China-based tech giant ByteDance, does not release data on what kind of reach posts receive, nor does the company publicly reveal what actions in takes against misinformation, unlike competing social media sites like Facebook and Twitter.

NPR talked to a dozen other young people using the app and watched them scroll through the app. There were plenty of fitness, skateboarding and cooking posts. But only a single video from Ukraine.

Still, TikTok researcher Richards worries about the impression fake war videos are having on young users.

"They haven't necessarily experienced a geopolitical conflict on this scale, and TikTok is where a lot of people, especially younger people, are going for their news and for their information and for their outlook on the world," she said.

As of Thursday, videos with the hashtag #RussianInvasion have received 88 million views and videos with the hashtag #RussiaUkraine have racked up 386 million views.

"This is the first time TikTok has really been central in a conflict situation of this scale," said Sam Gregory, the program director of Witness, a nonprofit focused on the ethical use of video in humanitarian crises.

"And the volume of misleading videos does seem new to me. Some people are doing it because they want attention, some people want to monetize it, others are doing it potentially as misinformation and disinformation," he said.

Some users are exploiting features that help videos on TikTok go viral, including reusing an audio clip with new footage.

Audio of gunfire uploaded from before the war started was used in more than 1,700 videos before it was removed, often featuring shaky camera footage to give the impression that it was capturing a conflict, according to Media Matters. The group also found that a video featuring audio from a 2020 explosion in Beirut was watched more than 6 million times in just 12 hours.

Why are people creating fake Ukraine footage?

Richards says there's no simple answer. Sometimes it's to chase views, likes, or money. When the war started, researchers found that people were pretending to be doing live TikToks videos from Ukraine and asking for donations. Some were scams.

"It's hard to really assign a motive to a lot of the misinformation, but it does seem to be connected often times to grifting," she said.

TikTok's community guidelines say it bans misinformation "that causes harm to individuals," such as videos that incite hate or prejudice. But footage misrepresenting scenes of war does not appear to explicitly violate the company's content policies.

"So much of this kind of content, this kind of activity, falls within the grey zone," said Ciarán O'Connor with the London-based Institute for Strategic Dialogue

TikTok spokeswoman Hilary McQuaide said the company has ramped up efforts to catch misleading war-related videos since the conflict broke out. She said TikTok teams up with independent fact-checkers to help root out out inauthentic and unsafe content. She said those efforts have been newly energized in the wake of Russia's invasion of Ukraine.

"We continue to closely monitor the situation, with increased resources to respond to emerging trends and remove violative content, including harmful misinformation and promotion of violence," McQuaide said.

She also said users can navigate to the app's Explore page and find the "digital literacy hub" on the app, a feature where users can learn how to differentiate between real and fake videos.

In the past two days, an NPR reporter was served up an unlabeled video showing a movie depiction of war that was viewed nearly 50 million times and prompted a conversation in the comments about whether it was Ukraine. An old Albanian training exercise purporting to show Ukraine that was seen almost 15 million times. And a 2014 video watched on the platform about 5 million times claiming to show Ukrainian and Russian soldiers "face to face."

TikTok's design creates something of a paradox: If you watch a video repeatedly to try to decipher whether it's authentic or return to one after conducting research, "you're telling the algorithm you want more of this," Gregory said.

Researchers like Gregory say TikTok can do more to give users tools to quickly figure out if a video is fake: the ability to do instant reverse image searches to see whether the video has circulated in the past and databases where users can go to see if popular videos have already been debunked.

Often if a video is fraudulent, TikTok commenters will point it out and the comment will rise to the top of the video's discussion section, but waiting for a TikTok user to figure out if a video is fake is often too little, too late, researchers say.

Gregory said TikTok has the potential to make humanitarian crises and wars more vivid and tangible to a massive audience who may not have otherwise engaged at all, but time spent watching fake videos of war does little to add to a person's understanding of a conflict.

"We shouldn't reject instantly that ephemeral moments in peoples' lives is bad. There can be ways TikTok can help people engage and have dialogue with people on the front lines," Gregory said. "But the challenge is finding those moments within all the manipulation."