The Israeli Embassy in Washington, D.C. was targeted on Wednesday by unknown perpetrators who sent an envelope filled with an unidentified white powder to the building.

The FBI is currently examining the suspicious envelope, which was found in the embassy’s mailroom at approximately 4:00 p.m. EDT.  It was addressed to the embassy itself and not to any one person in particular.

Officers from the local metropolitan police department, DC Fire Department and EMS, Haz-Mat division and the U.S. Secret Service immediately dispatched units to the scene.

No one opened the envelope, according to embassy spokesman Jonathan Peled, who added that officials have no idea who sent it.

Peled told the Associated Press Wednesday night that a hazardous materials team is conducting tests on the substance, which was initially feared to contain the highly contagious anthrax bacteria, which has in the past been used as a biological weapon in the United States. 

The embassy spokesman added that there have been no illnesses or threats associated with the envelope. The building was not evacuated, and no injuries were reported.