Xinhua News Agency said the blast went off Thursday near a newspaper stand as the American, who is studying in China, was passing by. The American was slightly injured in the leg and taken to hospital.

Beijing police are investigating the cause of the explosion.

Xinhua did not say whether the injured person was a man or woman.

Officers were seen vacuuming up debris at the site hours after it happened and checking trash bins.

Such an explosion is rare for Beijing, which has a relatively low rate of crime and violence. The capital city is the seat of China’s government and has a heavy police presence.