Two senior members of Congress, Senate Minority Leader Charles E. Schumer (D-N.Y.) and Sen. Tom Cotton (R-Ark.), asked U.S. intelligence officials late Wednesday to determine whether the Chinese-owned social-networking app TikTok poses “national security risks.”

In a letter to Joseph Maguire, the acting director of national intelligence, the lawmakers questioned TikTok’s data-collection practices and whether the app adheres to censorship rules directed by the Chinese government that could limit what U.S. users see. TikTok, which provides users a feed of short videos, has become wildly popular among teenagers worldwide.

“With over 110 million downloads in the U.S. alone, TikTok is a potential counterintelligence threat we cannot ignore,” wrote Schumer and Cotton, who sits on the Senate Intelligence Committee. “Given these concerns, we ask that the Intelligence Community conduct an assessment of the national security risks posed by TikTok and other China-based content platforms operating in the U.S. and brief Congress on these findings.”

In response, TikTok leaders — writing in an unsigned blog post Thursday — sought to stress their independence from China. The company said it stores U.S. user data inside the United States and that it is not “subject to Chinese law,” while stressing it has “never been asked by the Chinese government to remove any content and we would not do so if asked.”

The request adds to growing regulatory headaches in the United States for TikTok and its parent company, ByteDance. The app’s meteoric rise has coincided with heightened political tensions between Washington and Beijing, driven largely by a trade war that has hurt both nations’ economies.

The dispute also has ensnarled U.S. corporate giants, including the National Basketball Association, whose attempts to appease China have angered U.S. lawmakers and others who question whether the sports league is capitulating on political expression and freedom of speech.

China’s growing tech industry and global ambitions long have been characterized as a threat by the U.S. government and Silicon Valley, which argue that a shift in technological dominance to the world’s second-largest economy could imperil American business, research and national security. Facebook chief executive Mark Zuckerberg raised similar concerns in a speech in Washington last week, fearing the Chinese government’s “Great Firewall” might affect even what U.S. users of Chinese-based apps might consume.

In their letter, Schumer and Cotton questioned TikTok’s terms of service, saying the app collects a wide array of data, including information about a user’s location. TikTok officials say U.S. users’ data is stored in the United States, but the lawmakers said they feared that TikTok “is still required to adhere to the laws of China.”

That could “compel Chinese companies to support and cooperate with intelligence work controlled by the Chinese Communist Party,” they wrote.

Schumer and Cotton further raised the possibility that TikTok follows Chinese censorship regulations and limits videos on sensitive political topics, including recent protests in Hong Kong. A review of TikTok conducted by The Washington Post earlier this year found that the service carried far fewer videos related to those demonstrations than other popular social media sites such as Twitter.

And the lawmakers said that TikTok could be a “potential target of foreign influence campaigns like those carried out during the 2016 election on U.S.-based social media platforms.” Russian-backed agents spread disinformation on Facebook, Twitter and other social media sites in the last presidential election, and Facebook recently revealed a new Russia-based effort targeting the 2020 race.

TikTok has declined repeatedly to discuss its content-moderation policies, including those involving disinformation.

The letter to Maguire marks the second congressional request for the government to delve into TikTok. Earlier this month, Sen. Marco Rubio (R-Fla.) called on the Committee on Foreign Investment in the United States, which reviews the national-security implications of foreign acquisitions, to investigate the 2017 purchase by ByteDance of Musical.ly, an app that ByteDance merged with its own offering to create TikTok.

At the time, Rubio said the “Chinese government’s nefarious efforts to censor information inside free societies around the world cannot be accepted and pose serious long-term challenges to the U.S. and our allies.”