In certain corners of the internet, the organizing prowess of K-pop fans — the typically young and diverse international enthusiasts of Korean pop music who congregate daily on social media — has long been the stuff of legend: Through coordinated group action, so-called fan armies of acts like BTS and Blackpink make sure that their favorite idols are trending topics who lead the music charts and sell out stadiums from South Korea to the Rose Bowl in Los Angeles and Citi Field in New York.

Now, amid a pandemic, a forthcoming presidential election and inescapable conversations about race, this loose collective of digital warriors is trying to exert its influence in a new realm: the American political arena.

Spurred at first by the ongoing Black Lives Matter protests around the world, K-pop stans made themselves known outside of music circles this weekend, when some took credit for helping to inflate expectations for President Trump’s rally in Oklahoma by reserving tickets they had no plans to use. But while the Trump campaign has denied that the pointed prank affected rally attendance, blaming protesters and the news media instead, the call to action in K-pop circles revealed a growing realization that fans’ efficient social-media tactics for fund-raising or making a song go viral can also be used for political activism.

In recent weeks, K-pop devotees — who use Twitter as a home base, but proliferate across TikTok, Facebook, Instagram and other platforms — have spammed a birthday card for President Trump, disrupted a Dallas police app seeking intelligence on protesters and flooded would-be white supremacist hashtags, while also announcing that they had matched a $1 million donation from BTS for Black Lives Matter groups. And in keeping with the growing popularity of K-pop in the United States, many of these budding digital activists may also be American citizens, according to experts.

“The English-speaking K-pop fans who are getting involved in this, who are up on these issues, these are not foreigners,” said CedarBough Saeji, an academic who studies K-pop fan culture. “These are Americans.”

“That these young, socially progressive, outward-looking people who are really adept at using these online platforms — who are stuck at home and online even more because of Covid-19 — that these people are doing political things is not surprising,” added Ms. Saeji, a visiting assistant professor of East Asian culture at Indiana University Bloomington. “These are young people who are completely willing to learn about a new culture to follow their interest in some pop-culture product. These are exactly the kind of people who are the opposite of the Trump audience that claps when he disses ‘Parasite’ and says that ‘Gone With the Wind’ is a real movie.”

In the days since Mr. Trump’s rally in Tulsa, no evidence has emerged that South Korean fans of K-pop were involved in any significant way in the “no-show” campaign. South Korean news media instead relayed American reports from Tulsa, treating the episode mainly as a gag by teenage fans of K-pop and TikTok users in the United States.

South Koreans tend to follow U.S. elections closely because they could affect alliance relations between Washington and Seoul, and American policy on North Korea. But they generally remain wary of taking sides in U.S. politics. Mr. Trump has been quite popular among liberal South Koreans, including young people, by raising hopes that his diplomacy with North Korea’s leader, Kim Jong-un, might produce a breakthrough in long-stalled talks on ending the North’s nuclear threat and establishing peace on the Korean Peninsula.

On Monday, some South Koreans responded to the news from Tulsa by expressing concern about how Mr. Trump might react. “Why does K-pop meddle in an American political dispute,” wrote one reader of a local newspaper article about the rally.

But while K-pop culture in South Korea is a largely apolitical mainstream concern, leaving fan armies to focus on boosting album sales and propping up their idols, the community’s position as a subculture in the United States may lend itself to more radical gestures, especially at a time of increased political polarization.

“Although K-pop’s message is not necessarily political in an overt sense, they are often about empowerment and self-confidence,” said the author of the “Ask a Korean!” blog, who uses the pen name T.K. Park. “Lots of first-time K-pop fans, for example, got into BTS because the group’s message of ‘love yourself’ strongly resonated with them.” And since such content has attracted an audience made up largely of women and people of color, Mr. Park added, “this message pushes them to be more expressive with every aspect of their lives, including politics.”

They had also already honed the necessary skills. “K-pop fans learned how to organize through their fandom,” Mr. Park said. “K-pop is a digital-native music,” he added, and South Korea’s early adoption of nationwide broadband service “made Korean pop music respond to the demands of the internet, and also made K-pop’s fandom the most sophisticated actors in the digital sphere.” He pointed to the near-constant campaigns to flood radio stations with song requests or sell out concert tickets in a matter of minutes as a training ground: “All of these activities can be translated into politics very easily.”

Nicole Santero, a fan and Ph.D. student with a focus on the BTS Army who also runs the data-focused @ResearchBTS account, found that in May, there were only two days when a term related to the group was not trending worldwide on Twitter.

“Sometimes they don’t even mean to trend, but there’s so many of them that sometimes they accidentally trend random words,” she said. “They’re really, really passionate people who just fight for what they love. Those characteristics translate well when you look at social issues.”

A spokeswoman for Twitter said that K-pop was the most tweeted about music genre worldwide, with more than 6.1 billion tweets in 2019, an increase of 15 percent from the year before. BTS was the most tweeted about artist for the last three years, the company added. TikTok and Facebook declined to provide data.

The recent turn toward political activism in the United States also follows a concerted effort by K-pop fans in recent years to make positive change en masse, in part as a reaction to the groups’ reputations as superficial, silly and even menacing mobs. Like the most fervent fan bases of American pop stars — including Justin Bieber’s Beliebers, Beyoncé’s BeyHive or Nicki Minaj’s Barbz, known collectively as “stans” after the Eminem song about an obsessive stalker — K-pop followers have been accused of harassment for piling onto critics or rivals. In South Korea, they have also been viewed as overly fawning, and even cultlike, banding together, for instance, to buy presents like luxury watches for famous singers.

But these days, philanthropic donations to uncontroversial causes like the poor, the old or the terminally ill — often in made in the name of chosen artists — are more common. “This was a way to remake fandom in the eyes of the public,” Ms. Saeji said.

Black Lives Matter in particular may have represented an urgent cause to K-pop fans given the artists’ debt to hip-hop culture and black music, with groups like BTS having been accused in the past of cultural appropriation. “Artists, directors, writers, dancers, designers, producers, stylists in the K-pop industry are all inspired by black culture whether they acknowledge it or not,” the South Korean singer and rapper CL wrote recently on Instagram.

“You have K-pop fans educating other K-pop fans about this,” Ms. Saeji said, noting the overarching enthusiasm across subjects both serious and playful. “You can go on K-pop Twitter and you will see somebody post about Black Lives Matter and then 10 minutes later post something about the cutest idol that they are totally fan-girling over. They don’t see a contradiction there.”

“What’s really important about this entire thing is that young people are seeing their political power, they are flexing and they are feeling it,” she added. “And you know what they are going to do next? They are going to vote. These K-pop fans are not feeling cynical right now. They are feeling empowered.”

Taylor Lorenz contributed reporting from New York; Choe Sang-Hun contributed reporting from South Korea.