Across the city, Prime Minister Recep Tayyip Erdogan's supporters gathered in their thousands for a campaign-style rally as he sought to galvanize his base after weeks of anti-government protests left his international image battered, and exposed deep rifts within Turkish society.
Police in uniform and plain clothes sealed off Taksim Square and adjacent Gezi Park, which riot police cleared of thousands of peaceful protesters in a swift but muscular operation Saturday evening.
Crews worked through the night to remove all traces of a sit-in that started more than two weeks ago and became the focus of the strongest challenge to Prime Minister Recep Tayyip Erdogan in his 10 years in office.
A combination photo shows a protester being sprayed by the police's water cannon during a demonstration at Kizilay square in central Ankara. (Reuters)
Istanbul's governor, Huseyin Avni Mutlu, said the square was off-limits to the public for the time being, and nobody would be allowed to gather. A spokesman for the protesters vowed the group would retake Gezi Park.
"We will win Taksim Square again and we will win Taksim Gezi Park again," Alican Elagoz said.
A call went out for another demonstration in Taksim Square for Sunday afternoon, but the area was within a tight police cordon and passers-by were being subjected to identity checks and bag searches.
Thousands of protesters trying to reach the area were stuck on side streets and in nearby neighborhoods in a blanket of tear gas. Stumbling to avoid the gas, they piled into nearby cafes and restaurants, where waiters clutched napkins to their faces.
Stone-throwing youths and riot police clashed in Istanbul's Sisli neighborhood next to the Taksim area. Television footage showed police deploying two water cannon trucks against the youths, standing near a flaming barricade blocking the street. Rocks littered the roadway.
In a district about 10 kilometers (six miles) from Taksim, Erdogan, who has repeatedly insisted that the protests were part of a plot by bankers and foreign media to destabilize Turkey, was preparing to deliver a speech to thousands of supporters at a political rally.
A similar speech in Ankara on Saturday before the raid was attended by tens of thousands, who cheered him as he warned protesters that security forces "know how to clear" the area.
The protests in Istanbul began as an environmental sit-in to prevent a development project at Gezi Park, but anger over a violent crackdown there on May 31 quickly spread to dozens of cities and spiraled into a broader expression of discontent with what many say is Erdogan's increasingly authoritarian decision-making.
He vehemently denies the charge, pointing to the strong support base that helped him win a third consecutive term with 50% of the vote in 2011.
The protests have left at least five people dead, including a police officer, according to a Turkish rights group, and more than 5,000 injured, denting Erdogan's international reputation.
In clashes that lasted through the night and into the morning in Istanbul, Turkey's largest city, protesters set up barricades and plumes of tear gas rose in the streets.
A woman is attacked by water cannon during protests in Kizilay square in central Ankara. (Reuters)
Television footage showed police detaining medical personnel who had been helping treat injured protesters, leading them away with their hands cuffed behind their backs.
Riot police also entered a shopping mall in an upscale neighborhood of central Istanbul, apparently searching for protesters.
In Ankara, the capital, police ratcheted up the pressure in the early afternoon, firing water cannon, rubber bullets and tear gas at central Kizilay Square.
At least four people were injured. Earlier, police had dispersed hundreds who tried to hold a memorial service for a protester who died of injuries sustained in a nearby police crackdown on June 1.
As a water cannon trucks sped into the Ankara square, four men ripped off the Turkish flags dangling off the sides of some vehicles. One of the men kissed the flag he had taken, clutched it to his breast, and then wheeled around to shake a fist at the truck's crew, shouting: "You don't deserve this!"
In Saturday's raid, hundreds of white-helmeted riot police swept through Gezi Park and Taksim Square at dusk, firing canisters of acrid, stinging gas. Thousands of peaceful protesters, choking on the fumes and stumbling among the tents, put up little physical resistance.
"We condemn the police assault with rubber bullets, intense tear gas and sound bombs on Gezi Park at a time where the park was populated with women, children and the elderly," said Taksim Solidarity, an umbrella group that emerged as the most prominent in the park's occupation.
Two men, one holding a banner with photos of three victims killed during protests, shout anti-government slogans as Turkish riot police spray water cannon at demonstrators who remained defiant after authorities evicted activists from an Istanbul park, making clear they are taking a hardline against attempts to rekindle protests that have shaken the country, in city's main Kizilay Square in Ankara, Turkey. (AP)
As police cleared the area, many protesters ran into hotels for shelter.
A stand-off developed at a luxury hotel on the edge of the park, where police opened up with water cannons against protesters and journalists outside before throwing tear gas at the entrance, filling the lobby with white smoke.
At other hotels, plain-clothes policemen turned up outside, demanding the protesters come out.
As the tear gas settled, bulldozers moved into the park, scooping up debris and loading it into trucks.
Crews of workmen in fluorescent yellow vests and plain-clothes police went through the abandoned belongings, opening bags and searching their contents before tearing down the tents, food centers and library the protesters had set up in what had become a bustling tent city.
Huseyin Celik, the spokesman for Erdogan's Justice and Development Party, told NTV that the sit-in had to end.
"They had made their voice heard. Our government could not have allowed such an occupation to go on until the end," he said.