The first demonstrations on Saturday were small, but the situation escalated after a forceful response by riot police. Two people were thought to have been killed and a further 1000 injured with the unrestrained use of teargas, said Amnesty International, while the Interior Ministry announced that 1700 had been arrested. Muammer Guler, the Interior Minister said 58 civilians and 115 security officers had been injured.
Protests have now taken place in 67 cities across Turkey, with police again using teargas yesterday to control crowds marching on the Prime Minister's office in Ankara, the capital.
The outpouring of opposition has presented the biggest challenge to Erdogan's leadership since he won power in 2002.
For the past decade, Turkey's economy has blossomed in a region where its neighbours are gripped by war or financial collapse. Inequality and poverty have declined - and the Government has won three elections.
But, buoyed by his victories, Erdogan has taken a series of bold policy decisions that, in the eyes of many, expose the Islamist outlook of his ruling Justice and Development Party (AKP) and seem increasingly oppressive for secular Turks.
"We don't feel we have true freedom in our country. He keeps banning many things," said a 27-year-old in Istanbul, Gokhan, as he sat nursing bruises from a night of clashes with the police. "The people have been putting up with these policies, but now they are full. They have had enough."
Two weeks ago, the Government banned the sale of alcohol between 10pm and 6am and then called any Turks who drank "alcoholics". Many secularists interpreted this move as the social imposition of Erdogan's religious conservatism.
The Prime Minister also wants to rewrite the constitution to create a powerful presidency.
Many of the demonstrators in Istanbul yesterday were young and secular - although older people came to their front doors and banged pots and pans in a show of solidarity. "The AKP are trying to delete everything from our republic; they are trying to destroy everything that Ataturk built up," said one young man, referring to the leader who created modern Turkey as a secular republic in 1923.
Erdogan has acknowledged that "there have been some mistakes, extremism in [the] police response". He added: "They call me a dictator. If they liken a humble servant to a dictator, then I am at a loss for words."
Yesterday, smashed pavements showed where people had torn up paving stones for use as missiles against the police. One police car lay upturned in the pond of the Hyatt hotel. At one point protesters drove a mechanical digger to break through police lines, right up to a government building. The police pushed the protesters back. The test will be whether the demonstrations are sustained.
"This will not be forgotten," said one marcher. "It is not only in Istanbul it is across the whole country. We have a saying, everything is Taksim, and everything is Gezi Park".
From a nearby rooftop, a banner with the words "Do not surrender" was unfurled.
