Parts of the federal government are pulling back from advertising on TikTok, according to an advertising executive who works with government agencies, as the U.S. government restricts federal employees’ and contractors’ use of the app, a unit of China’s ByteDance.

Last week, NASA, the Department of Defense and the General Services Administration issued an interim rule prohibiting contracts that would require using TikTok, including “where social media advertising services might be part of the procurement.” The rule effectively prohibits government advertising on TikTok, according to policy experts.