More than a dozen lawmakers called on the Department of Commerce on Thursday to add ByteDance, the Beijing-based parent company of TikTok, to its export control list in order to “address critical vulnerabilities created by the company’s access to U.S. software.”

The group, led by Reps. Dan Crenshaw (R-Texas) and Josh Gottheimer (D-N.J.), expressed concerns about the security of U.S. user data on TikTok, as well as the relationship between ByteDance and the Chinese government.

“TikTok provides the [Chinese Communist Party] with the ability to weaponize the platform by suppressing, magnifying, and otherwise constructing narratives to target specific audiences abroad,” the lawmakers said in a letter to Commerce Secretary Gina Raimondo.

“Applications from ByteDance are an accessory to the soft power and propaganda of the CCP, and we must mitigate the role of software access in facilitating this capability,” they added.

The lawmakers urged Raimondo to add ByteDance to the Bureau of Industry Security’s Entity List. The export of goods, software and technology to companies on the list are restricted.

“This step would be instrumental in applying licensing restrictions to the export of software from the U.S. to ByteDance for its applications,” they said.

“If American users are not able to upgrade their app with software updates, which involves the export of U.S. software, then the operability of the applications of concern will be weakened,” the lawmakers added.

TikTok CEO Shou Zi Chew, who appeared before Congress last week alongside four other tech CEOs to testify about children’s safety online, emphasized that TikTok has not shared user data with the Chinese government.

He also pointed to the social media company’s initiative known as Project Texas, which aims to wall off U.S. user data from the rest of the company.

However, lawmakers have expressed doubts about Project Texas, particularly after the Wall Street Journal reported last week that employees have sometimes been directed to share data with other parts of TikTok and ByteDance.

“Not only does this letter misrepresent the facts and the law, it also ignores the industry leading work we’ve done to safeguard protected U.S. user data,” a TikTok spokesperson said in a statement. “We’ve engaged in good faith with Congress and relevant agencies through the [Committee on Foreign Investment in the United States] process for over four years and continue to do so.”

Updated at 10:52 a.m. ET