Taksim Square erupted in chaos on Tuesday night as the riot police hit protesters with tear gas and water cannons, sending thousands of people fleeing down side streets, and Prime Minister Recep Tayyip Erdogan of Turkey struggled to contain a political crisis that has threatened the nation's economy and paralyzed the government.
For nearly two weeks, the prime minister has remained largely defiant, demanding that protesters leave the square, placing armed police officers on standby to sweep the area and insisting that the demonstrations were nothing like the Arab Spring protests that ousted entrenched leaders.
But as homemade firebombs and tear gas wafted in the city center it seemed that Mr. Erdogan and his supporters had miscalculated the opposition's tenacity and conviction.
"Thugs! Thugs!" a protester shouted at the police as she was shrouded in a cloud of tear gas. "Let God bring the end of you!"
The demonstrations began over a plan to tear out the last green space in the center of the city, Gezi Park in Taksim Square, and to replace it with a mall designed like an Ottoman-era barracks. Mr. Erdogan, who once advised the Syrian president, Bashar al-Assad, to negotiate and compromise, sent out the police to clear the park.
The tactic backfired, leading to large protests and expressions of frustration at Mr. Erdogan's rising authoritarian streak. Environmentalists and conservationists were joined in the protest by radical leftists and street hooligans.
Mr. Erdogan pulled back the police, but for days Taksim has been a sprawling and eclectic hub of grievance against him and his Justice and Development Party.
On Monday, he offered to talk on Wednesday — but then sent the police back to clear the square Tuesday.
At first, the city center took on the feel of a movie set: fireworks ignited by protesters and nonlethal sound bombs set off by the police punctuated the chants of "Istanbul is ours! Taksim is ours!"
(Slideshow: Turkish Turmoil-Scenes From the Turkey Protests)