The US Secret Service is investigating after cocaine was found at the White House on Sunday night.
The discovery in the West Wing, which contains the Oval Office and other working areas for presidential aides and staff, led to a brief evacuation.
Secret Service agents found the suspicious powder in an area that is accessible to tour groups while doing a routine inspection.
President Joe Biden and his family were at Camp David in Maryland at the time.
A senior law enforcement official told the BBC’s US partner CBS News the substance was found in a storage facility routinely used by White House staff and guests to store mobile phones.
The White House complex was closed as a precaution around 20:45 local time (00:45 GMT) on Sunday after it was discovered.
A preliminary test, which was first reported by the Washington Post, later confirmed it was cocaine.
The Secret Service will lead a full review of how the substance got into the White House, officials told CBS. They said cameras and entrance logs would be examined to determine who had access to the area where it was found.
Cocaine is a Schedule II drug under the Controlled Substances Act, meaning it has a high potential for abuse, according to the US Drug Enforcement Administration.
The West Wing is a large, multi-level part of the White House that contains the offices of the president of the United States, including the Oval Office and the Situation Room.
It also houses the offices of the vice-president, the White House chief of staff, the press secretary, and hundreds of other staff who have access.