Turkey’s PM Recep Tayyip Erdogan has vowed to press ahead with plans to redevelopment a park in Istanbul which have sparked violent clashes.
Mr Erdogan said he would not yield to “wild extremists” but that police may have used “excessive” force.
Police have now withdrawn from Istanbul’s Taksim Square, which has become the focus of the protests.
Correspondents say the local issue has spiralled into widespread anger over perceived “Islamisation” of Turkey.
Mr Erdogan has been in power since 2002 and some in Turkey have complained that his government is becoming increasingly authoritarian.
His ruling AK Party has its roots in political Islam, but he says he is committed to Turkey’s state secularism.
Turkish media reaction
Murat Yetkin in the in pro-secular, English-language daily Hurriyet says the “disproportionate” response of police to the protests “has managed to turn a pacifist and modest protest into a public protest movement”.
Ali Bayramoglu, writing in the pro-government Islamist daily Yeni Safak asks how the authorities allowed the situation to get so bad. “If there is a public reaction, why won’t it [the governent] halt the project, even temporarily, and talk to the protestors?”
In Islamist daily Today’s Zaman, Ihsan Yilmaz says that if the government does not listen to the protesters the park issue “may be the last straw and may pave the way for the eventual electoral loss of the city”.
Last week, Turkey’s parliament approved legislation restricting the sale and consumption of alcoholic drinks between 22:00 and 06:00.
The clashes over Gezi Park, next to Taksim Square, broke out Friday and continued there and in the capital, Ankara, on Saturday.
Opponents of the plan say the park is of the few green areas left in central Istanbul – many had been camping out there for several days in protest.
But in a defiant speech to the exporters’ union, Mr Erdogan insisted the project would go ahead, and that the historic Ottoman era military barracks would be rebuilt on the site as planned.
Referring to the protesters’ fears that the site will actually become a shopping mall, he said one “might be built on the ground floor or a city museum. We haven’t given our final decision yet”.
Mr Erdogan vowed order would be restored “to ensure the safety of people and their property” and that police would stay in place “because Taksim Square cannot be an area where extremists are running wild”.
He said of the protests: “All attempts apart from the ballot box are not democratic”, adding that he could summon a million pro-government protesters if he wanted to and accusing his opponents of using the issue as an excuse to create tension.
What began as a small scale, peaceful protest to clear Gezi Park, one of the few remaining green spaces left in Taksim, has escalated into some of the worst scenes of public disorder and police violence seen in Turkey in recent years.
I was at Gumussuyu, on the edge of Taksim, at around 22:00 last night. Vast, blinding clouds of pepper spray and tear gas were being deployed by baton-wielding officers in riot gear who turned on thousands of protesters.
Bricks and paving slabs were pulled up and used as missiles by the crowds. Police in vehicles drove at them in an attempt to get them to disperse. With Taksim closed, demonstrators massed in the surrounding areas of Cihangir and Beyoglu and anti-government slogans and chanting continued through the night.
Despite the damage done to property, the police force “continues to operate with the authority it was given,” said Mr Erdogan.
However, he did admit that the police response may have been “excessive”, and that the interior ministry was investigating the “misuse of tear gas by our security forces”.
Turkey’s President Abdullah Gul has called on all sides to be “mature” in order for the protests which he said had reached “a worrisome level, to calm down.”
In a statement, he called on the police to “act in proportion”.
The protest began at the start of the week as a sit-in in Gezi Park to block the redevelopment plans. But they escalated after police used tear gas to try to clear the protesters out.
On Friday, a dozen people were admitted to hospital and more than 60 people detained as police and protesters clashed.
Then on Saturday, hundreds of demonstrators marched over the bridge connecting the Asian and European shores of Istanbul to try to reach the Taksim Square.
Police again fired tear gas and water cannon to clear protesters, sparking accusations of excessive force.
Demonstrators, some of whom threw rocks, chanted “unite against fascism” and “government resign”.
One Istanbul resident, who gave her name as Lily, told the BBC’s World Service that police had dropped tear-gas canisters from helicopters overnight.
Protests in Ankara continued into Saturday
“About half past one the entire city started to reverberate. People were banging on pots, pans, blowing whistles,” she said.
Another woman protesting in Istanbul told Agence France-Presse: “They want to turn this country into an Islamist state, they want to impose their vision all the while pretending to respect democracy.”
Later on Saturday afternoon, there were cheers in the square as the police withdrew their vehicles and took down barricades, apparently allowing the protest to go ahead.
Clashes were also reported in the Besiktas district while in Ankara, hundreds of demonstrators gathered at a park, many drinking alcohol in protest at the new restrictions.
The BBC’s Louise Greenwood in Istanbul says police from as far afield as Antalya are being drafted in to help quell the violence.
The US has expressed concern over Turkey’s handling of the protests and Amnesty International condemned the police’s tactics.
In his speech, Mr Erdogan criticised the “preaching” of foreign governments, saying they “should first look at their own countries”.