Leaders at Oracle, the main cloud computing provider for TikTok's U.S. operations, have told some staff to prepare to shut down servers that host U.S. TikTok data on Saturday night as early as around 9 p.m. Eastern, in advance of a U.S. law that bans the app starting Sunday.

Oracle CEO Safra Catz is expected to give the final go ahead to cut off the TikTok servers, according to a person with direct knowledge of the plan. Her involvement reflects the magnitude of the shutdown. The app, owned by China's ByteDance, says it has 170 million users in the U.S. TikTok is one of Oracle's biggest cloud customers, and Oracle has warned shareholders that the ban would hurt its revenue and profits.