ISTANBUL (AP) - Turkish Prime Minister Recep Tayyip Erdogan said on 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, Mr 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 10km away in central Istanbul, riot police fired tear gas and used water cannon on thousands of defiant protesters attempting to regroup and demonstrate again in the city's main Taksim Square. Clashes broke out in nearby neighbourhoods with stone-throwing young people.

Protesters are angry over the eviction of overwhelmingly peaceful activists at Gezi Park, next to Taksim Square, who oppose government plans to rip down its trees and erect a replica Ottoman-era barracks. But the protests quickly spiraled into a widespread denunciation of what many say is Mr Erdogan's increasingly authoritarian way of governing - charges he vehemently denies.

Speaking to his supporters, Mr 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 officers in uniform and plain clothes sealed off Taksim Square and Gezi Park, which riot police cleared of thousands of peaceful protesters in a swift but muscular operation on 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 Mr Erdogan in his 10 years in office.

Istanbul 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," Mr Alican Elagoz said.

Thousands of protesters trying to reach the area were stuck on side streets and in nearby neighbourhoods 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 young people and riot police clashed in Istanbul's Sisli neighbourhood next to the Taksim area. Television footage showed the police deploying two water cannon trucks against the young people, standing near a flaming barricade blocking the street. Rocks littered the roadway.

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.

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.