Policemen inspect the explosion site in Beijing, capital of China, Oct. 21, 2010. An explosion happened beside Dongzhimenwai Street in Beijing on the afternoon of Oct. 21, leaving a national of the United States slightly injured in a leg. (Xinhua/Gong Lei)

The blast happened at 3:20 p.m. Thursday beside a newspaper stand near the Dongzhimen subway station in Dongcheng District, police said in a press release.

Police said a 30-year-old American studying in China, who happened to pass by, was slightly injured in the leg and had been rushed to a nearby hospital.

Police are investigating the cause of the blast.