Police in the western Turkish city of Istanbul have attacked anti - government protesters camped out in the city’s Gezi park.

Thousands of people took to the streets of Istanbul overnight on Sunday, erecting barricades and starting bonfires, after riot police firing teargas and water cannon stormed the park at the center of two weeks of anti - government demonstrations.

Lines of police backed by armoured vehicles sealed off Taksim Square in the center of the city as officers raided the adjoining Gezi Park late on Saturday, where protesters had been camped in a ramshackle settlement of tents.

Prime Minister Tayyip Erdogan had warned hours earlier that security forces would clear the square, the center of more than two weeks of fierce anti - government protests that spread to cities across the country, unless the 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 his supporters at a rally in Ankara. Protesters took to the streets in several neighbourhoods across Istanbul following the raid on Gezi Park, ripping up metal fences, paving stones and advertising hoardings to build barricades and lighting bonfires of trash in the streets.

Some chanted, " Tayyip, resign, " Reuters reported.

Local television footage showed groups of demonstrators blocking a main highway to Ataturk airport on the western edge of the city, while to the east, several hundred walked towards a main bridge crossing the Bosphorus waterway towards Taksim.

Thousands more rallied in the working - class Gazi neighbourhood, which saw heavy clashes with police in the 1990s, while protesters also gathered in Ankara around the central Kugulu Park, including opposition MPs who sat in the streets in an effort to prevent the police from firing teargas. A main public - sector union confederation, KESK, which has some 240,000 members, said it would call a national strike for Monday, while a second union grouping said it was holding an emergency meeting to decide whether to join the action.

“One million people to Taksim " - a call for more anti - government demonstrations later on Sunday - was a top - trending hashtag on Twitter.

" The police brutality aims at clearing the streets of Istanbul to make way for Erdogan ' s meeting tomorrow, " said Oguz Kaan Salici, Istanbul president of the main opposition People ' s Republican Party.

" Yet it will backfire. People feel betrayed. "

Meanwhile, Erdogan said Thursday that he would put the controversial redevelopment plans for Gezi Park on hold until a court rules on them. It was a softer stance after two weeks in which he called protesters " riff - raff " and said the plans would go ahead regardless.