Two envelopes containing ricin were sent to the Pentagon

Two packages containing a suspicious substance were delivered to the Pentagon. The envelopes were addressed to Pentagon chief James Mathis and Navy commander John Richardson.

The FBI said the suspect substance was discovered during an inspection at the agency's post office, after which the envelopes were seized for testing. According to a CNN source, preliminary tests showed that they contained ricin .

• In the United States, government agencies and politicians have repeatedly received letters containing ricin in recent years. The recipients were not informed of any serious health consequences.