A package has ignited at a postal facility in Washington, a day after two parcels exploded when they were opened in the nearby state of Maryland.
FBI spokeswoman Lindsay Godwin said initial information showed the package was similar to the two parcels opened at state office buildings in Maryland on Thursday.
The packages in Maryland contained a message complaining about electronic highway road signs that asked motorists to report suspicious activity.
Police officer Hugh Carew said no injuries had been reported following the Washington incident and the building had been evacuated.
The Maryland packages, addressed to Governor Martin O’Malley and Transportation Secretary Beverley Swaim-Staley, have been taken to an FBI lab for forensic analysis.
They were opened within a 15-minute period at state government buildings 20 miles apart.
The workers who opened them singed their fingers but there were no significant injuries.
Postal Service spokeswoman Joanne Veto said the Washington package was discovered after another package was thrown on top of it. She said the labels, postmark and stamps were similar to the Maryland parcels.