Turkish Prime Minister Recep Tayyip Erdogan said Sunday it was his "duty" to order riot police to evict activists occupying an Istanbul park that became a centre of defiance against his rule, even as the government crackdown continued across town with tear gas fired at protesters trying to regroup.

In a thunderous speech to hundreds of thousands of supporters in western Istanbul, Erdogan also railed against foreign media coverage of the unrest amid criticism over his government's handling of the protests that left his international image battered, and exposed deep rifts within Turkish society.

About 10 kilometres away in central Istanbul, riot police fired tear gas  and used water cannons  on thousands of defiant protesters attempting to regroup and demonstrate again in the city's main Taksim Square. Clashes broke out in nearby neighborhoods with stone-throwing youths.

Speaking to his supporters, Erdogan recalled telling Interior Ministry officials: "You are going to clear Gezi Park. We have reached an end. We cannot stand it anymore.' And as you know, yesterday the operation was carried out, and it was cleared."

"I did my duty as prime minister," he said, "Otherwise there would be no point in my being in office."

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 Erdogan in his 10 years in office.

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.

Pro-government rally

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.

Erdogan 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.

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Supporters of Prime Minister Tayyip Erdogan's ruling AK party arrive for a rally in Istanbul on Sunday. (Murad Sezer/Reuters)

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 per cent 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.

Memorial service for protester

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. 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!"

One-day strike

Turkey's Confederation of Public Workers' Unions (KESK), which  has some 240,000 members in 11 unions, and the Confederation of Revolutionary Trade Unions (DISK) announced a nation-wide strike for Monday in a joint statement.

Three other groups representing engineers, dentists and doctors will also join them in the strike, it said.

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.

Shelter in hotels

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.

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People throw stones at water cannons during a protest at Kizilay square in the capital city of Ankara on Sunday. (Dado Ruvic/Reuters)

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.