(Reuters) - Police in the Myanmar city of Mandalay opened fire and used tear gas on Saturday to break up an anti-coup protest but it was not clear if they fired live ammunition or rubber bullets, according to video broadcast by a media outlet. A doctor told the Irrawaddy news site that several people had suffered from exposure to tear gas and one person was wounded by a bullet but it could have been a rubber bullet. Police were not immediately available for comment.