A package discovered smouldering at a postal facility in the United States capital Washington DC was addressed to the country's Homeland Security Secretary, Janet Napolitano.
The building in the north east of the city was evacuated after the parcel ignited on Friday, and officials say no-one was hurt.
They say the device was similar to two others sent to government offices in the neighbouring state of Maryland a day earlier.
They emitted smoke when they were opened, and contained notes criticising anti-terrorism signs on roads in Maryland.
