Turkish riot police have stormed a central Istanbul park firing tear gas and water cannon to evict hundreds of anti-government protesters, hours after an ultimatum from Prime Minister Tayyip Erdogan.
Lines of police backed by armoured vehicles sealed off Taksim Square in the centre of the city as officers stormed the adjoining Gezi Park, where protesters had been camped.
Mr Erdogan had warned hours earlier that security forces would clear the square, the centre of more than two weeks of fierce anti-government protests, unless demonstrators withdrew before a ruling party rally in Istanbul on Sunday.
"We have our Istanbul rally tomorrow. I say it clearly: Taksim Square must be evacuated, otherwise this country's security forces know how to evacuate it," he told tens of thousands of flag-waving supporters at a rally in Ankara.
Panicked protesters fled into an upscale hotel at the back of the park, several of them vomiting, as clouds of tear gas and blasts from what witnesses said were percussion bombs - designed to create confusion rather than injure - engulfed the park.
Residents in surrounding neighbourhoods took to their balconies or leaned out of windows banging pots and pans, their clatter rising above the wail of ambulance sirens, while car drivers sounded their horns in support of the protesters.
Several people were brought out of the park on stretchers to waiting ambulances, while families with young children fled into side streets from a main shopping street leading to the square.
A similar police crackdown on peaceful campaigners in Gezi Park two weeks ago provoked an unprecedented wave of protest against Mr Erdogan, drawing in secularists, nationalists, professionals, trade unionists and students who took to the streets in protest at what they see as his autocratic style.
The unrest, in which police fired tear gas and water cannon at stone-throwing protesters night after night in cities including Istanbul and Ankara, left four people dead and about 5,000 injured, according to the Turkish Medical Association.
The protesters, who oppose government plans to build a replica Ottoman-era barracks on Gezi Park, had defied repeated calls to leave, but had started to reduce their presence in the park after meetings with Mr Erdogan and the local authorities.