Senate Minority Leader Chuck Schumer (D., N.Y.) is raising concerns about the U.S. Army’s use of video-sharing app TikTok and other China-owned social media platforms for recruiting efforts, citing the potential for personal data to be shared with the Chinese government.

“National security experts have raised concerns about TikTok’s collection and handling of user data,” Mr. Schumer wrote in a Nov. 7 letter to Army Secretary Ryan McCarthy. He said this information could be compromised “in light of laws that compel Chinese...