Thai police blasted protesters with water cannon and used teargas on Tuesday, hurting several people in a bid to push back a demonstration at parliament demanding constitutional changes that would touch on the powerful monarchy.br br Protesters are demanding changes to the constitution drawn up by a former junta. They also want the removal of Prime Minister Prayuth Chan-o-cha, a former army ruler, and reforms to curb the powers of King Maha Vajiralongkorn.