SHANGHAI — The video app TikTok on Wednesday reversed its decision to block an American teenager who posted a clip in which she discussed the mass internment of minority Muslims in China, and acknowledged that its moderation system had overreached in shutting her out of her account.
The incident raised fresh concerns about whether TikTok, which is owned by the Chinese tech giant ByteDance, muzzles its users in line with censorship directives from Beijing — an accusation the company has denied.
TikTok said the teenager, Feroza Aziz, 17, had been barred from using her personal device to access the app, but not because of her video this past week about China’s detention camps. Rather, the company said, it was because she had used a previous account earlier this month to post a clip that included a photo of Osama bin Laden.
After TikTok banned that account for terrorist imagery, Ms. Aziz used a different one to post her video about the plight of Muslims in China. As the second video began to go viral, TikTok on Monday blocked more than 2,400 devices associated with accounts that had been banned for terrorist content and other malicious material, in what it called a scheduled enforcement action.
This, TikTok said, resulted in Ms. Aziz being locked out from her new account, even though her videos on that account, including the one on China, were still visible to others.
On Wednesday, Ms. Aziz expressed skepticism about TikTok’s explanation. She was blocked only after she had posted about Muslims in internment camps in China. Did she believe that TikTok had actually shut her out for her earlier video? “No,” she wrote on Twitter.
Earlier in the day, the episode had taken another turn when TikTok took down Ms. Aziz’s video about China for 50 minutes. The company said that this was the result of a human moderation error, and that the video should not have been removed.
In a statement, Eric Han, the head of safety for TikTok in the United States, apologized for the mistake. He also said the platform banned devices associated with a blocked account to prevent the spread of “coordinated malicious behavior.”
“It’s clear that this was not the intent here,” Mr. Han wrote.
Earlier this week, Ms. Aziz had told The Times that her video containing an image of Bin Laden was satirical in nature, an attempt to use humor to defuse the discrimination that she felt as a young Muslim in the United States.
“While we recognize that this video may have been intended as satire, our policies on this front are currently strict,” Mr. Han wrote. But he added that TikTok would consider exempting satirical and educational videos in the future.
Mr. Han also said TikTok would conduct a broader review of its moderation process and publish a “much fuller” version of its guidelines on acceptable content within the next two months.
TikTok has risen quickly over the past year to become a veritable cultural phenomenon. But its Chinese ownership has also aroused the concerns of United States lawmakers, who have voiced worries both about potential censorship on the platform and about how user data is stored and secured.