Two U.S. senators have asked the Federal Trade Commission to investigate TikTok’s data collection practices after a Wall Street Journal article showed that the company covertly collected data on millions of users through a method that appeared to violate Google’s policies.

Sens. Jerry Moran (R., Kan.) and John Thune (R., S.D.) made the request in a letter addressed to FTC Chairman Joseph Simons. The senators urged Mr. Simons to “investigate the company’s consumer data collection and processing practices as they relate to these accusations and other possible harmful activities posed to consumers.”

“While we understand and appreciate the various national security concerns raised against TikTok to date, the purpose of this inquiry is to raise specific attention to the practice highlighted in the mentioned reports,” the senators said in a letter Thursday.

The Journal reported on Tuesday that TikTok, owned by Beijing-based ByteDance Ltd., bypassed a privacy safeguard in Google’s Android devices to collect unique identifiers, called MAC addresses, from millions of mobile devices. The collected identifiers, often used for online advertising, would allow the company to track users’ online behavior without their consent.

TikTok collected MAC addresses for at least 15 months, ending with an update released Nov. 18 of last year, as ByteDance was falling under intense scrutiny in Washington, the Journal’s testing showed. The senators asked the FTC to investigate whether the company had stopped collecting these unique identifiers.