Authorities said item addressed to US head of homeland security shared likeness with others found day before

A package addressed to the head of US homeland security that ignited at a Washington DC postal office yesterday was similar to two others that detonated in nearby Maryland on Thursday, US authorities said.

No one was injured, but the FBI and US Postal Service said the item was very similar to the two packages found the day before.

Cathy Lanier, the Washington DC chief of police, described the package as "popping, smoking, and with a brief flash of fire. Then it went out – extinguished itself". Washington police said that they had evacuated the building when the device went off.

Officials told a US TV station that the package, which ignited at a US Postal Service facility about four miles from the White House, was addressed to Janet Napolitano, the homeland security secretary. A second package was also reportedly found, but failed to go off.

The US Postal Service said the Washington package ignited when a worker threw it into a sorting bin at about 2.45pm, local time. A spokeswoman said the labels, postmark and stamps were similar to the Maryland parcels.

When the first two packages, sent to Maryland governor Martin O'Malley and the state's transport secretary, Beverley Swaim-Staley, were opened, they gave off flames and smoke, and slightly burned the hands of the workers who were holding them. Investigators said the packages, which were roughly the size of books, contained notes complaining about electronic roadside signs that tell people to report anything unusual, such as terrorism.

"Report suspicious activity! Total bullshit! You have created a self fulfilling prophecy," read one of the messages.

Police said the two packages were opened on Thursday within 15 minutes of each other. One ignited in the mailroom of the Maryland Department of Transport in the town of Hanover. The other went off in a mail-handling facility 20 miles away in a state building in the city of Annapolis.

Both Maryland packages apparently contained a battery and an electric "sparker", but no other explosive material. The contents of the Washington package have not yet been revealed. The remains of the first two packages have been taken by the FBI for forensic analysis, but police said they had not identified any suspects.