Turkish police fired tear gas and water cannons at peaceful protesters as they entered their fourth day of demonstrating in Istanbul's central Taksim Square.

The Occupy-style sit-in began earlier this week when trees in the square's park were uprooted as part of a government redevelopment plan, but the movement has since expanded to a broader protest against the government of Turkish Prime Minister Recep Tayyip Erdogan.

"This isn't just about trees anymore, it's about all of the pressure we're under from this government," one 18-year-old protester told Reuters.

Erdogan's administration has arrested human rights activists and journalists, and it's enacted restrictions on alcohol and public kissing, among other things, in an attempt to pivot the country toward Islamic culture and values.

At least 100 people have been injured in today's clashes so far, some of them seriously. Here are some of the photos from the site:

A Turkish riot policeman uses tear gas as people protest against the destruction of trees in a park in Taksim Square on May 28, 2013. (Reuters)

A woman is sprayed with tear gas by a Turkish riot policeman on May 28, 2013 (Reuters)

A Turkish riot policeman uses tear gas as a demonstrator holds a banner which reads "Chemical Tayyip," referring to Prime Minister Tayyip Erdogan, during a protest on May 31, 2013. (Reuters)

A demonstrator falls after being hit by water cannon on May 31, 2013. (Reuters)

The words on the men's shirts read, "People's Republican Party Young Members Group". (Reuters)

A demonstrator reacts as riot police use a water cannon and tear gas to disperse the crowd on May 31, 2013. (Reuters)

A demonstrator reacts as riot police use water cannons to disperse the crowd on May 31, 2013. (Reuters)