A developing report says packages delivered to the Pentagon’s mail facility tested positive for ricin on Tuesday.

Local news affiliate FOX 5 DC says that the mail did not enter the Pentagon, according to U.S. officials. Both Pentagon Force Protection and Federal Bureau of Inspection (FBI) agents are on scene for additional testing of received mail.

At this time, Pentagon personnel have not been evacuated from the premises.

Pentagon spokesman Chris Sherwood said in a statement that at least two pieces of mail were suspected of containing the poison, which according to the Centers for Disease Control and Prevention, “if it is made into a partially purified material or refined, ricin can be used as a weapon capable of causing death under certain circumstances.”

In a separate statement, Col. Rob Manning announced all U.S. Postal Service mail sent to the Pentagon’s mail facility is presently “under quarantine” and “poses no threat to Pentagon personnel.”

CNN national security reporter Ryan Browne says the packages were addressed to Defense Secretary James Mattis and Chief of Naval Operations John Richardson.