U.S. regulators have opened an investigation into ByteDance, the Chinese owner of TikTok, and its acquisition of Musically in late 2017, Reuters reported Friday morning. Regulators are said to focus on potential national security risks, given that ByteDance is based in China.

The investigation is being handled by the Committee on Foreign Investment in the United States, which usually reviews these kinds of deals as they happen. However, since ByteDance didn’t seek approval for the deal when it happened, regulators are looking into it now, according to the report.

Senate Minority Leader Chuck Schumer (D-N.Y.) and Senator Tom Cotton (R-Ark.) jointly called for such an investigation last month, at the time calling TikTok “a potential counterintelligence threat we cannot ignore.”

“We are not influenced by any foreign government, including the Chinese government,” TikTok said at the time in response to Schumer’s and Cotton’s demands. “TikTok does not operate in China, nor do we have any intention of doing so in the future.”

ByteDance acquired Musically for $1 billion in November of 2017, and subsequently merged the app with its own TikTok video service.

There have been reports that TikTok censored some posts about pro-democracy protests in Hong Kong in recent weeks, but the company has denied this charge. “TikTok does not remove content based on sensitivities related to China,” the company said. “We have never been asked by the Chinese government to remove any content and we would not do so if asked. Period.”