On Wednesday, two senior senators, Chuck Schumer (D-NY) and Tom Cotton (R-AR), took aim at the Chinese-owned video app, TikTok, and called for US intelligence officials to investigate it for any threats to national security it may pose.

The letter to Director of National Intelligence Joseph Maguire, which was first reported in The Washington Post on Thursday, prompts officials to investigate TikTok’s data collection practices to determine whether the Chinese government has any say in what content Americans see on the app.

“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,” Schumer and Cotton wrote.

Over the past year, lawmakers have grown more and more concerned over companies that operate in the US with ties to China. Last summer, China hawks like Cotton and Sen. Marco Rubio (R-FL) launched attacks against telecom companies like Huawei and ZTE regarding their allegiance to the Chinese government. In recent weeks, much of this same criticism has pivoted toward TikTok, a video-sharing app that has skyrocketed in popularity with American users.

In their letter, Schumer and Cotton write that TikTok has received over 110 million downloads in the US alone.

“We do not have details on the request and will not be offering any further comment on it at this time other than to reaffirm that TikTok is committed to being a trusted and responsible corporate citizen in the US, which includes working with Congress and all relevant regulatory agencies,” a TikTok spokesperson told The Verge.

Earlier this month, Rubio wrote to Treasury Secretary Steven Mnuchin asking that the Committee on Foreign Investment in the United States (CFIUS) investigate TikTok for potential national security threats and censorship as well. In September, The Guardian reported that TikTok requires its moderators to censor any content that refers to Tiananmen Square, Tibetan independence, or Falun Gong. The company maintains that these are outdated guidelines, and TikTok moderators receive no input or influence from the Chinese government.

“These Chinese-owned apps are increasingly being used to censor content and silence open discussion on topics deemed sensitive by the Chinese Government and Community Party,” Rubio said at the time.