A white powder that was found in the White House and sparked a brief security alert has been confirmed to be cocaine, the Secret Service has said.
The powder's discovery in the West Wing on Sunday was initially treated as a potential danger, prompting a brief evacuation.
An initial test of the substance performed by the Washington DC fire department then said it appeared to be cocaine - not some sort of threat or attack.
This prompted a flurry of speculation in US media over who could have left the drug. President Joe Biden and his family were away from the White House all weekend.
White House spokesperson Karine Jean-Pierre told reporters: "Where this was discovered is a heavily traveled area where many ... West Wing visitors come through."
Asked whether anyone had undergone drug testing as part of the investigation, Ms Jean-Pierre said: "We will take any action ... that is appropriate and warranted, pending the outcome of Secret Service."
The West Wing is attached to the executive mansion where President Joe Biden and first lady Jill Biden live.
It includes the Oval Office, cabinet room and work space for presidential staff. Hundreds of people pass through the West Wing on a regular basis, including political staff, their guests and members of the press.
Ms Jean-Pierre said West Wing tours took place on Friday, Saturday and Sunday.
The substance was found during a routine Secret Service sweep on Sunday evening. A Secret Service spokesperson did not respond to requests for comment this evening. The agency has not said how much cocaine was found.
The discovery led to a brief closure of the White House complex on Sunday. Mr Biden and his family were not at the White House then.
Mr Biden did not answer questions that reporters shouted at him about the cocaine today. The president thinks it's "incredibly important" to get to the bottom of it, Ms Jean-Pierre said.
Administration officials are able to offer tours of parts of the West Wing to friends and family members. People who are not members of staff must leave electronics and other belongings in the storage cubicles before taking a tour.
