Turkey police renew sweep in Istanbul's Taksim Square, clash with protesters Updated 4:30 p.m. ISTANBUL Protesters and Turkey's prime minister both refused to back down Tuesday in what could become the final battle for Istanbul's Taksim Square, the symbol of nationwide grievances against his government. Tens of thousands of protesters returned to the square in the evening, in a show of defiance met with tear gas, rubber bullets and water cannons, hours after riot police had forced their way past improvised barricades to clear the square of protesters occupying the area for the past 12 days. Hundreds more vowed to continue their sit-in at Taksim's adjacent Gezi Park, despite an order from Prime Minister Recep Tayyip Erdogan for them to leave - an order bolstered by the police show of force. A peaceful demonstration against the park's redevelopment that began more than two weeks ago has morphed into the biggest test of Erdogan's authority in his decade of power. The unrest has spread to 78 cities across the country, with protesters championing their objections to what they say is the prime minister's increasingly authoritarian style and his perceived attempts to impose a religious and conservative lifestyle in a country with secular laws - charges he rejects. So far four people have died, including a policeman, and about 5,000 have been treated for injuries or the effects of tear gas, according to the Turkish Human Rights Foundation. Tuesday's clashes, which saw police and protesters take and lose control of the square several times, came a day after Taksim saw its smallest gathering since the demonstrations began, sparked by a violent police reaction against a sit-in in the park to prevent its redevelopment. The government had also said Erdogan would meet with some of those occupying the park on Wednesday to hear their views. "The relative calm yesterday was deceptive," said Robert O'Daly, Turkey analyst for the Economist Intelligence Unit. Mr. Erdogan's offer of dialogue appears to have been merely tactical. The appearance of riot police in the square this morning and renewed use of teargas against the protesters fits better with his defiant rhetoric," said O'Daly. Yet as he defended his tough stance, he gave critics little hope of a shift in his position. "Were we supposed to kneel before them and say 'please remove your pieces of rags'?" he said, referring to the dozens of banners and flags the protesters had festooned in the square. His words, accompanied by the repeated rounds of tear gas that left many choking for breath, seemed to gird the resolve of many in the park rather than weaken it. People are definitely going to stay. The more the police attack, the more people come and stay," said Melda, a 29-year-old cook who rushed to the park Tuesday morning when she heard of the police intervention. Fearful of losing her job for participating in the protests, she asked that her surname not be used. Melda and a group of friends had originally intended to go and set up a stall giving out cupcakes and sandwiches to the protesters. Instead they arrived with first aid supplies. She had harsh words for those protesters who had thrown rocks and firebombs at riot police on the square earlier in the day. "They're taking advantage of the situation," she said. And then the prime minister calls us all terrorists. On Tuesday, Erdogan, who has called major pro-government rallies in Ankara and Istanbul this weekend, insisted again that the unrest was part of a conspiracy against his government. In Taksim, unrest continued into the night. The tens of thousands of protesters who returned in the evening were met with more rounds of tear gas, which was also fired into the park. Students clutching surgical masks, women in summer dresses and sandals, and boys selling gas masks ran through the trees for cover from the plumes of acrid chemicals that spewed out of canisters fired by riot police. Istanbul Governor Huseyin Avni Mutlu asked peaceful protesters to stay away from Taksim until it was cleared of "marginal groups." He said some 30,000-35,000 had gathered as police stood by. Police fired tear gas to disperse them because some attacked police. Ambulances ferried away the injured. Before the evening clashes, more than 300 people had already been treated in a makeshift infirmary set up in the park, most for the effects of tear gas, said volunteer Selin Akuner. Twelve had suffered head injuries. In the square, water cannons doused a man in a wheelchair carrying a Turkish flag as a phalanx of helmeted officers moved forward. Plainclothes officers in gas masks yanked down banners for the second time in a day. Barcin Yinanc, a columnist for the Istanbul-based Hurriyet Daily News, said Erdogan's speech indicated he wouldn't allow the occupation of Gezi Park for much longer. "If there is a very serious clampdown, then I think that the protesters will continue to react against the government," she said. However, he estimated they were unlikely to continue as they had. Many believe that the message to the government was given sufficiently loud enough and that the opposition to the government should now move off the streets and be channeled through other ways. But as night fell to the echoes of exploding tear gas canisters in Taksim, few protesters appeared willing to leave.