Dozens of protesters gather in front of Capitol Hill as Japanese Prime Minister Shinzo Abe pays a visit to White House in Washington D.C., capital of the United States, April 28, 2015. Nearly 200 people held signs and shouted slogans in a protest against Abe's handling of history issues, demanding the Japanese leader to unequivocally apologize for his country's wartime crimes here on Tuesday. (Xinhua/Bao Dandan)