A group of Republican lawmakers are calling on their colleagues to stop using TikTok as pressure mounts to ban the app nationwide.

In letters to the Senate and House rules committees, Sen. Marsha Blackburn (R-TN), Rep. Dan Crenshaw, and more than a dozen other Republicans demanded that the panels ban elected officials from using TikTok. Last year, Congress and a handful of state legislatures banned the app on government-owned devices, but these rules do not currently apply to members’ personal phones and devices. 

“It is troublesome that some members continue to disregard these clear warnings and are even encouraging their constituents to use TikTok to interface with their elected representatives — especially since some of these users are minors. We feel this situation warrants further action to protect the privacy of both sensitive congressional information and the personal information of our constituents,” the lawmakers wrote. 

In order to approve a ban on officials using TikTok, the committees would need to amend standing House and Senate rules to include language barring members from using the app. It’s likely that they would hold hearings related to the proposed change before putting the new language up to a series of votes for approval.

Even though Congress has moved to ban TikTok over the last few months, some lawmakers have continued to use the app to engage with their constituents online. Many members who use TikTok, like Rep. Jamaal Bowman (D-NY), have garnered significant followings by posting videos explaining legislation and responding to news events. 

Bowman, who has over 200,000 followers on TikTok, led a press conference at the Capitol last month opposing a ban on the app. More than 20 TikTok creators, flown out by the company, and two other House Democrats joined Bowman at the presser. Since the event, more Democrats, including Reps. Alexandria Ocasio-Cortez (NY) and Ilhan Omar (MN), have made statements condemning efforts to ban the app. 

“If we want to make a decision as significant as banning TikTok, and we believe — or someone believes — that there is really important information that the public deserves to know about why such a decision would be justified, that information should be shared,” Ocasio-Cortez said in a TikTok video last month. 

In March, the House Energy and Commerce Committee brought in TikTok’s CEO Shou Zi Chew to respond to questions about the app’s security practices. For more than three years, lawmakers have argued that the app, owned by Chinese company ByteDance, could be used by the Chinese government to spy on American citizens.

“Some members of Congress who regularly use the app have minimized the security threat to our nation, and their defense is not compelling, considering there are several popular social media apps that are not at the same risk for the potential transfer of sensitive, private information to an adversarial foreign government,” the lawmakers wrote.