Turkish police attacked Newroz celebration in Amed/Diyarbakir

Turkish police attacked Newroz celebration in Amed/Diyarbakir 
Police used tear gas, water cannon and rubber bullets to stop Kurds to enter Newroz square in Diyarbakir on Monday 21 of March 2016.
But thousands of Kurds break through a police barricade and quickly moved into the Newroz square 
After 2 hours number of Kurds in inside Newroz square reached near one million.
Its hard to understand why Turkish police attacked Kurdish Newroz celebration while they had legal approval from the Mayer for Newroz celebration on that day.