Two or more packages delivered to the Pentagon this week were suspected to contain the deadly poison ricin, an official said Tuesday.
Defense Department spokesman Chris Sherwood said at least two suspicious packages were intercepted at a nearby screening center on Monday.
"As part of the screening process, (authorities) recognized some suspicious packages," Sherwood said, noting they were "suspected to be ricin."
He stressed that authorities were still waiting for confirmation that the packages contained ricin. Pentagon police referred the matter to the FBI for investigation.