Sarajevo. A gunman with an automatic weapon opened fire at the United States embassy in the Bosnian capital Sarajevo on Friday and police rushed to the scene, a Reuters witness said. A Reuters photographer said police were trying to surround the gunman, who was armed with a Kalashnikov rifle. A source close to the embassy said two security guards had been wounded. The U.S. embassy is located in the central business, university and shopping district of the capital.