|The package scare prompted a quick response from the fire department [EPA]
A parcel has ignited at a postal facility in Washington DC, a day after two similar incidents in mailrooms in the US state of Maryland, police officials say.
No one was reported injured in Friday's incident, and the Washington postal facility was evacuated.
"There was an ignition of some envelope or package," Hugh Carew, a police spokesman, told Reuters news agency.
"They evacuated the building, and we're investigating at this time."
The incident prompted concerns following two similar cases on Thursday in nearby Maryland. Two separate packages ignited in state government buildings, one a mailroom in the capital Annapolis and another at the state transportation headquarters in Hanover.
FBI Spokeswoman Lindsay Godwin said initial information indicated the parcel that ignited in Washington was similar to the two packages opened in Maryland on Thursday.
The packages, addressed to Governor Martin O'Malley and to Transportation Secretary Beverley Swaim-Staley, have been taken to an FBI lab for forensic analysis.
They were opened within a 15-minute period on Thursday at state government buildings 32km apart.
Soon after, mailrooms across Maryland were cleared and two other suspicious packages uncovered, though they turned out to be a toner cartridge and laptop batteries.
Explosive material wasn't found in either package that ignited and authorities aren't sure if any other dangerous packages are out there, but mailroom employees were back at work on Friday. They had pictures of the packages and were advised to be vigilant about anything suspicious.
Postal Service spokeswoman Joanne Veto said the suspicious 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.