The FBI on Tuesday launched an investigation into packages believed to contain the deadly poison ricin that were sent to someone at the Pentagon.

Pentagon spokesman Chris Sherwood said at least two packages were intercepted at a delivery facility on Pentagon grounds and not at the defense department's main five-sided building.

Read more: German health minister talks bioterrorism in White House

What we know so far:

• The packages were addressed to one person. The Pentagon would not reveal that person's name.
• Authorities have quarantined all US Postal Service mail received at the Pentagon's screening facility. The Pentagon said it "poses no threat to Pentagon personnel."
• Some reports said the packages had been sent to US Defense Secretary James Mattis. Leading Navy Admiral John Richardson may have also been an addressee, according to US officials speaking on condition of anonymity.
• The packages are "currently undergoing further testing," according to the FBI.

Read more: Ricin — an easy-to-obtain bio-weapon from the internet

Deadly poison

Ricin is a poison derived from castor beans that can easily be overlooked as the cause of death at autopsy. There is no known antidote to ricin but emergency medical care immediately after exposure can prevent death.

In 2013, several letters containing ricin were sent through the US Postal Service, including one intercepted in Washington DC and addressed to former President Barack Obama.

ls/msh (AFP, AP)

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