Turkish riot police fought running battles with pockets of protesters overnight, clearing the central Istanbul square that has been the focus of nearly two weeks of protests against Prime Minister Tayyip Erdogan.

By dawn, Taksim Square, strewn with wreckage from bulldozed barricades, was largely deserted and taxis crossed it for the first time since the troubles started. Several hundred remained in an encampment of tents in Gezi Park abutting the square.

Erdogan, who has repeatedly dismissed the demonstrators as "riff-raff", was expected to meet a grouping of public figures about the protests on Wednesday. In the fighting talk that first endeared him to voters 10 years ago, he said on Tuesday he would not "kneel" before the protesters and that "this Tayyip Erdogan won't change".

The United States, which has held up Erdogan's Turkey in the past as an example of Muslim democracy that could benefit other countries in the Middle East, expressed concern about events in Turkey and urged dialogue between government and protesters.

"We believe that Turkey's long-term stability, security and prosperity is best guaranteed by upholding the fundamental freedoms of expression, assembly and association, and a free independent media," White House spokeswoman Caitlin Hayden said.

Erdogan, though, has increasingly accused foreign forces and international media and market speculators of stoking conflict and trying to undermine the economy of the only largely Muslim NATO state.

He has also exerted strong pressure on the media, seven newspapers last week carrying the identical headline citing Erdogan as saying he, not the protesters, guaranteed democracy.

The night had brought some of the worst clashes since the troubles began. Police fired tear gas into thousands of people gathered on the square, including people in office clothes who had gathered after work, some with families with children.

The crowd scattered into narrow streets around, leaving a hard core of protesters to return, lighting bonfires and stoning water cannon. Police then launched tear gas attacks again, the cycle repeating itself until numbers dwindled.

"We will continue our measures in an unremitting manner, whether day or night, until marginal elements are cleared and the square is open to the people," Istanbul Governor Huseyin Avni Mutlu declared on television on Tuesday night.

Police were less in evidence by the morning and it was not clear if protesters would return in the course of the day, as they have previously.

A fierce crackdown on initial protests against planned redevelopment of Gezi Park, a leafy corner of Taksim, triggered the wider protests, drawing in a broad alliance of secularists, nationalists, professional workers, unionists and students - some of whom would never before have considered sharing a political platform.

Erdogan argues that the broader mass of people is at best the unwitting tools of political extremists and terrorists and points to his 50 percent vote in the last of three successive electoral victories for his political authority.

His critics, some of whom who say conservative religious elements have won out over centrist reformers in his AK Party, accuse him an increasingly authoritarian conduct and of inflaming the crisis with unyielding talk.

Some charge that his politics are too often shaped by a religious agenda, with the introduction of alcohol restrictions and comments suggesting he favors a traditionalist role for women.

For his part, Erdogan has complained of the contempt he feels secularist leaders have shown in the past for religious sentiments, excluding women with head scarves from universities. He has accused protesters of attacking women in headscarves and of desecrating mosques by bringing in beer.

"There's no room for dialogue when there's ongoing violence," said Mucella Yapici of the Taksim Solidarity Platform, a core group behind the Gezi Park campaign.

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