Standoff as man in pickup near US Capitol claims he has a bomb

A pickup truck is parked on the sidewalk in front of the Library of Congress' Thomas Jefferson Building, as seen from a window of the US Capitol. Photo / Alex Brandon, AP

A man sitting in a black pickup truck parked on the sidewalk outside the US Library of Congress told police he had a bomb Thursday (local time), triggering a standoff in the heart of the nation's capital.

Officials evacuated buildings around the Capitol and sent snipers to the area after officers saw the man holding what looked like a detonator inside the pickup, which had no licence plates. Congress is in recess this week, but staffers were seen calmly walking out of the area at the direction of authorities.

Police negotiators were communicating with him as he wrote notes and showed them to authorities from inside the truck, according to three people who were not authorised to publicly discuss the matter and spoke on condition of anonymity. They were trying to determine whether it was an operable bomb, the officials said.

"My negotiators are hard at work trying to have a peaceful resolution to this incident," US Capitol Police Chief J Thomas Manger said. "We're trying to get as much information as we can to find a way to peacefully resolve this."

People are evacuated from the James Madison Memorial Building, a Library of Congress building, in Washington. Photo / Alex Brandon, AP

The episode began about 9.15am when the truck drove up the sidewalk outside the library, Manger said. The driver told the responding officer that he had a bomb, and was holding what the officer believed to be a detonator. The truck had no licence plates.

The nation's capital has been tense since the January 6 insurrection at the Capitol by supporters of then-President Donald Trump.

Fencing that had been installed around the Capitol grounds had been up for months but was taken down this summer. A day before thousands of pro-Trump rioters stormed the Capitol, pipe bombs were left at the headquarters of the Democratic National Committee and the Republican National Committee in Washington. No one has been arrested yet for placing the bombs.

The RNC, not far away from where the truck was parked Thursday, was also evacuated over the threat.

The area was blocked off by police cars and barricades, and multiple fire trucks and ambulances were staged nearby. Also responding were the District of Columbia's Metropolitan Police, FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives.

The White House said it was monitoring the situation and was being briefed by law enforcement. - AP