Helmeted police with batons and riot shields advanced on protesters in Thailand on Friday (October 16) -- the most violent escalation of three months of anti-government demonstrations. As thousands of protesters defied a ban on protests for a second day, Thai police fired water cannon at them. Reuters journalists at the scene said the water contained chemicals to make it sting. Undeterred, protesters threw plastic bottles at police. The protests are aimed at the king and the prime minister, in the biggest challenge for years to an establishment long dominated by the army and the palace. For months, they have largely been peaceful, and until now, police had not used major force to suppress them. But more than 40 demonstrators, including several leaders, have been arrested in the past week. Some have called out insults against the king -- something that until recently was almost unheard of in a country where the constitution says he must be revered. In one incident on Wednesday, police pushed jeering protesters away from a motorcade carrying the queen. On Thursday, the government banned political gatherings of five or more people. Those marching on the streets want a new constitution and a reduction in the powers of the king. (c) 2020 Thomson Reuters, unless otherwise identified.