The U.S. Secret Service evacuated a government office building near the White House, closed down adjacent streets and cleared pedestrians from sidewalks on Wednesday in response to a suspicious vehicle in the area.

The Secret Service said in a post on Twitter that two blocks bordering the White House had been closed to traffic.

Witnesses said authorities turned away federal workers heading to the New Executive Office Building and cleared pedestrians from sidewalks. At least a dozen emergency vehicles had responded to the scene.

About 100 White House staff members were held in a park before authorities began letting some into the White House.

(Reporting by Makini Brice, Roberta Rampton, Ginger Gibson and Susan Heavey; Editing by David Alexander and Andrea Ricci)