A package addressed to Department of Homeland Security Secretary Janet Napolitano ignited today at a Washington, D.C. postal facility.
The package looked "similar" to the book-sized envelopes that detonated in Maryland on Thursday, officials said, but it was not immediately clear whether the incidents were related and whether the same person sent all three packages.
The Metropolitan Police Department received a call at 2:45 p.m. that a package had ignited in the 3300 block of V St. southeast, public information officer Lt. Nicholas Bruel told ABC News.
The package was not opened and it wasn't in the process of being opened. It ignited on its own and quickly burned out, FBI spokeswoman Lindsay Godwin told ABC.
DC Metro Police Chief Cathy Lanier said "there was popping, smoking, a brief flash of fire and then it extinguished itself."
She described the device as "similar in nature to the packages found yesterday."
No injuries were reported and the building was evacuated as a precautionary measure.
Lanier said extra protective measures were put into place in the district after the Maryland incident Thursday and that will continue to be the case.
"Right now we don't have any other packages but we're not taking anything for granted," she added.
U.S. postal service spokeswoman Irene Lericos said that the building is an annex that handles U.S. government mail.
FBI and Department of Homeland Security officials are on the scene and investigating the suspicious envelopes.
On Thursday, a pair of incendiary devices in small packages, including one addressed to the governor of Maryland, erupted within hours of each other inside two government office buildings in Maryland.
The detonations injured two people but there were no major injuries.
Those devices -- similar in construction to ones recently mailed to embassies in Rome and in Greece -- were described by one official as "terror vandalism," that are "intended to scare, and hurt you a bit, but not kill." Officials described them as powered by a small battery linked to an electric match and a switch.
A message linked to the devices suggested they were sent by someone who was angry with the government's terror warnings, sources told ABC News.
The devices carried the statement: "Report suspicious activity. Total bulls..t! You have created a self fulfilling prophecy," sources told ABC News.
The Maryland incidents have triggered a spike in suspicious activity in the region and put security on high alert.
At least one of the packages was sent from the address of an empty parking lot in Washington, D.C. in upper northwest Washington, D.C. near American University. Maryland law enforcement issued a bulletin warning post offices to steer clear of packages that bore the same address.
The devices that ignited in Maryland bore strong resemblance, including in size and packaging, to a series of recent bombings in Rome and an earlier string of similar attacks in Greece. Anarchists groups claimed credit for those attacks.
ABC News' Steven Portnoy contributed to this report.