By Humeyra Pamuk and Ece Toksabay
ISTANBUL (Reuters) - Turkish police fired teargas and water cannon to disperse hundreds of protesters in an Istanbul square on Saturday as they gathered to enter a park that was the center of protests against Prime Minister Tayyip Erdogan last month.
Taksim Solidarity, combining an array of political groups, had called a march to enter the sealed off Gezi park, but the governor of Istanbul warned that any such gathering would be confronted by the police.
"We are going to our park to open its doors to its real owners ... We are here and we will stay here ... We have not given up our demands," the umbrella group said in a statement.
Riot police chased protesters into side streets in what appeared to be the biggest police intervention since the mid-June protests and riots that saw Taksim Square sealed off by makeshift barricades.
"They can use Gezi Park as they wish, without gathering or demonstrating there ... If there is an illegal demonstration or march, of course we will intervene by using water cannons," Interior Minister Muammer Guler said.
Protesters in Istanbul chanted "Together against fascism" and "Everywhere is resistance".
Witnesses said that police detained dozens of protesters, but later in the evening many still remained in side streets in the Taksim area, including youths and women, some in gas masks.
"We are here today to claim our park back. It was supposed to be open tonight. They (authorities) called us occupiers, but the park has been occupied by the state for weeks now," said 41-year-old web designer Asim Elci.
A police crackdown on a group protesting against the planned redevelopment of Gezi Park, a leafy corner of Taksim, triggered nationwide protests last month against Erdogan, accused by critics of increasingly authoritarian rule after a decade in power.
In the capital, Ankara, hundreds of protesters took to the streets in one area close to the center.
Turkish Halk TV showed protesters standing in front of riot police in Istanbul, displaying a court decision cancelling plans for a replica Ottoman-era barracks on Taksim Square. The plan is one of a string of ambitious projects fostered by Erdogan, including a canal parallel to the Bosphorus waterway, a huge international airport and a giant mosque.
Authorities can appeal against the court ruling, which was considered a victory for the protesters and a blow for Erdogan, who stood fast against protests and riots he said were stoked by terrorists and looters.
Erdogan has carried out sweeping changes since he was elected in 2002 at the head of a party combining nationalists and reformers as well as Islamist elements. He had curbed the power of an army that had toppled four governments in 40 years and carried out some liberal social and economic reforms.
But critics, outside the party and some within, had grown increasingly uneasy at what they felt to be an authoritarian style. At the height of the protests he appeared to appeal increasingly to the Islamist and nationalist core of his party, further alienating secularists and other groups.
Four people were killed and about 7,500 wounded in the June crackdown, according to the Turkish Medical Association. It largely ended when police cleared a protest camp on the square on June 15.
Istanbul governor Huseyn Avni Mutlu said the authorities had not given permission for Saturday's rally.
"Our constitution allows staging demonstrations without giving notification, but the legislation says that applying to the authorities for permission is mandatory," Mutlu said, announcing on his twitter account that Gezi Park would be open to the public on Sunday.
(Additional reporting by Daren Butler; Writing by Parisa Hafezi; Editing by Ralph Boulton and David Goodman)