U.S. Capitol police on Thursday morning were urging people to stay away from the area near the Library of Congress as they conducted an “active bomb threat investigation” after a man drove a black pickup onto the sidewalk in front of the library's Thomas Jefferson Building at 9:15 a.m. ET and told an officer he had a bomb (article available here).
The U.S. Supreme Court was among the buildings that were evacuated. Other buildings evacuated were the Library of Congress; the Cannon, Jefferson and Madison office buildings, according to the Washington Post.
The man surrendered without incident on Thursday afternoon after a tense five-hour standoff. It's not clear if there was an actual bomb.