The Office of Management and Budget calls the guidance, issued Monday, a “critical step forward in addressing the risks presented by the app to sensitive government data.” Some agencies, including the Departments of Defense, Homeland Security and State, already have restrictions in place; the guidance calls on the rest of the federal government to follow suit within 30 days.

The White House already does not allow TikTok on its devices.

“The Biden-Harris Administration has invested heavily in defending our nation’s digital infrastructure and curbing foreign adversaries’ access to Americans’ data,” said Chris DeRusha, the federal chief information security officer. “This guidance is part of the Administration’s ongoing commitment to securing our digital infrastructure and protecting the American people’s security and privacy.”

The guidance was first reported by Reuters.

Congress passed the “No TikTok on Government Devices Act” in December as part of a sweeping government funding package. The legislation does allow for TikTok use in certain cases, including for national security, law enforcement and research purposes.

TikTok, owned by ByteDance Ltd, remains extremely popular and is used by two-thirds of teens in the U.S. But there is increasing concern that Beijing could obtain control of American user data that the app has obtained.

The company has been dismissive of the ban for federal devices and has noted that it is developing security and data privacy plans as part of the Biden administration’s ongoing national security review.

Canada also announced Monday that it is banning TikTok from all government-issued mobile devices. The European Union’s executive branch said last week it has temporarily banned TikTok from phones used by employees as a cybersecurity measure.