Washington D.C. mayor concerned about potential attack on city's residential area

Security staff are seen near the U.S. Capitol building in Washington, D.C., the United States, Jan. 17, 2021. Up to 25,000 National Guard members have been authorized for the city to ensure the security of Wednesday's inauguration, transforming the city into what some U.S. media called "a war zone." (Xinhua/Liu Jie)