WASHINGTON — Sen. Chuck Schumer is questioning the US Army’s decision to try to recruit Gen Z’ers using TikTok and other China-owned social media platforms, raising concerns about privacy and national security.

Schumer, a New York Democrat and the party’s leader in the Senate, wrote a letter to Army Secretary Ryan McCarthy on Nov. 7 requesting the military branch assess the national security risks associated with the platform. TikTok, a popular video-sharing application launched in 2017, became the US’s most downloaded app in 2018, with two-thirds of its users under the age of 30, according to a third party estimate. The Army turned to TikTok and other social media platforms in 2019 after recruiting numbers slumped the year before by more than 6,000 soldiers.

“While I recognize that the Army must adapt its recruiting techniques in order to attract young Americans to serve, I urge you to assess the potential national security risks posed by China-owned technology companies before choosing to utilize certain platforms,” Schumer wrote in the letter obtained by BuzzFeed News.

In the letter, Schumer also asks if the Army has consulted with the Department of Homeland Security regarding potential security risks and if the Army has considered alternative recruiting methods.

The letter is just the latest example of US officials raising security concerns about the app. Earlier this month, the Committee on Foreign Investment in the United States (CIFUS) — the government agency that oversees foreign investments into US companies or operations — launched a probe into TikTok’s Chinese parent company ByteDance because of censorship and national security concerns. TikTok and its parent company recently came under fire from Republican and Democratic congressional members. Former national security experts say the CIFUS probe signals an increased concern for national security.

“I think that what this does reflect is the national security community’s concern for data sources — not just data related to plans for the F35 or Department of Defense secret personnel data, but also personal data where there is a lot of it and the ability to analyze it is increasing,” John Dermody, a former official with the National Security Council and US Department of Homeland Security, told BuzzFeed News. “If you can identify networks of individuals or connections, then it can have a direct impact on national security concerns.”

Last month, Schumer partnered with Republican Sen. Tom Cotton to address similar national security concerns with TikTok in a bipartisan letter to acting director of National Intelligence Joseph Maguire. The lawmakers focused on the terms of service policies that allow TikTok to gather a user’s location, IP address, location-related data, device identifiers, cookies, metadata, and other sensitive information — data they say is subject to laws that mandate Chinese companies provide data for China’s intelligence work.

In a blog post last month, TikTok looked to “set the record straight” by clarifying that it stores all of its data in the United States with a backup in Singapore. “We are not influenced by any foreign government, including the Chinese government; TikTok does not operate in China, nor do we have any intention of doing so in the future,” the company wrote.

“While the company has stated that TikTok does not operate in China and stores U.S. user data in the U.S., ByteDance is still required to adhere to the laws of China,” Schumer wrote in the letter to the Army.

Even before the recruiting push, it was common to see military personnel posting TikToks from bases and barracks. This month, TikTok user Shafter Salladay posted a military-style version of the viral meme “fucking mint” where users sarcastically point out problems with their cars, homes, etc. Salladay created a spin-off version using a military-grade 18-wheeler.

“Dashboard doesn’t even work. Fucking mint,” they said in the video. “Missing half my dash lights here. Fucking mint.”

Last week TikTok was a no-show at a Senate subcommittee hearing on tech companies’ data handling chaired by Sen. Josh Hawley, who has been vocal about TikTok and Apple’s censorship and security concerns.

“We appreciate Sen. Hawley’s invitation. Unfortunately, on short notice, we were unable to provide a witness who would be able to contribute to a substantive discussion,” a ByteDance spokesperson said at the time.

“We remain committed to working productively with Congress as it looks at how to secure the data of American users, protect their privacy, promote free expression, ensure competition and choice among internet platforms, and preserve U.S. national security interests,” ByteDance added.

Ryan Mac contributed to this story.