The U.S. Embassy in Stockholm, Sweden, was briefly evacuated Wednesday after an alarm was raised over a suspicious envelope containing white powder, Stockholm police said.

Stockholm police are moving the envelope to a secure location in order to examine it, police spokesman Albin Navery said.

"The embassy has been evacuated and we are working with Swedish authorities to investigate the incident," a U.S. State Department official told CNN. All employees are accounted for, the official said.

The all-clear has now been given and staffers have begun to return to the building, CNN affiliate TV4 said.