Harris, then the vice-president elect and senator from California, evacuated the Democratic National Committee (DNC) headquarters on Capitol Hill after law enforcement officers discovered the device, said the official, speaking on condition of anonymity.

The U.S. Secret Service, which provides Harris' security, did not immediately respond to a request for comment.

For a year, the FBI has been looking for a suspect wearing a gray hooded top who they say planted an explosive device next to a park bench outside the DNC and another in an alley behind the Republican National Committee (RNC) headquarters. The devices, which officials believe were planted the night before, were defused.

Their discovery came on the same day as supporters of then-President Donald Trump stormed the Capitol in an attempt https://www.reuters.com/world/us/biden-call-trump-threat-democracy-us-capitol-attack-anniversary-2022-01-06 to overturn the Nov. 3, 2020, election of Joe Biden and Harris.

Harris, Biden and other lawmakers observed the anniversary with speeches at the Capitol on Thursday.

(Reporting by Trevor Hunnicutt, Editing by Rosalba O'Brien)

By Trevor Hunnicutt