MOSCOW - Vladimir Putin claimed victory in Russia's presidential election on Sunday and, tears rolling down his cheeks, said it was a historical turning point that had prevented the country falling into the hands of enemies trying to usurp power.The prime minister's opponents said there had been widespread fraud in Sunday's election. They refused to recognize the results and vowed to press on with the biggest protests since he rose to power 12 years ago.Challenges aheadDespite the growing opposition, mainly among well-educated and relatively well-off young professionals in big cities, Putin's support remains high in the provinces and his victory had not been in doubt.The main challenge for the man credited by many Russians with rebuilding the country's image and overseeing an economic boom, was to win outright in the first round.Putin is sure to portray his return to the post he held from 2000 until 2008 as strong public backing against the protesters, whom he has portrayed as a destabilising minority and pawns of foreign governments.But the reaction to his rallying cry at the victory rally was muted, and hundreds of buses had brought the crowd to the capital, signaling that it was a well-organized show of force rather than a spontaneous display of support.Putin, who will be inaugurated in May, will be taking power in a country where the mood has shifted and many people are uncertain whether he will be conciliatory and reformist, or stand in the way of political and economic change.He is likely to revert to his fighting talk against the West, a trademark of his first presidency and his election campaign, and sounded far from conciliatory on Sunday towards protesters questioning his democratic credentials and now the legitimacy of two elections.Economists say another key test of Putin's return will be how far he is ready to go to reform an economy heavily dependent on energy exports, and caution that his populist campaign spending promises could return to haunt him.'Leader of the nation'Putin has remained Russia's dominant leader and its most popular politician since stepping aside in 2008 to make way for his ally, Medvedev, because he was barred from a third straight term by the constitution.Some voters said Putin, who has portrayed himself as a man of action and guardian of stability, was the tough national leader the world's biggest country and energy producer needed."I voted for Putin because he was a good president (from 2000-08) and our children were looked after and that's all. That's how I feel," said Maria Fedotova, a 92-year-old grandmother in fur coat and hat, flanked by relatives.But others are tired of his macho antics, such as horse riding bare-chested, and a system that concentrates power in his hands. They fear he could win another term in six years and rule until 2024 - almost as long as Soviet dictator Josef Stalin."They are stealing our votes," said Valentin Gorshun, a patient in Moscow hospital number 19, where more than 90 percent of votes went to United Russia party in December."It is probably the same at all hospitals," he said. "I think they are preparing a huge falsification. Emperor Putin has decided everything."Thousands of opposition activists as well as an international observer mission were also monitoring the polls.Vote monitors from the opposition and bloggers posted allegations of election rigging across the country of 143 million. Golos, an independent monitoring group, said it had registered at least 3,100 reports of violations nationwide.An Interior Ministry spokesman denied there had been any major violations and Putin said he had won a "clean" victory. Election officials also dismissed reports of widespread fraud in the parliamentary election on Dec. 4.But the former KGB spy was triumphant, and unusually emotional, after exit polls and partial results suggested he would win about 60 percent of the vote and return to the Kremlin after four years as premier."I promised you we would win. We have won. Glory to Russia," Putin, dressed in an anorak and flanked by outgoing President Dmitry Medvedev, told tens of thousands of flag-waving supporters late in the evening at a victory rally meters from the red walls of the Kremlin.Denouncing attempts to "destroy Russia's statehood and usurp power", he declared: "The Russian people have shown today that such scenarios will not succeed in our land ... They shall not pass!"It was a defiant and angry speech in which Putin, 59, sounded a clear warning to the mainly middle-class protesters in Moscow and other big cities who have staged huge rallies since a disputed parliamentary poll on Dec. 4.Putin's nearest rival, Communist Party leader Gennady Zyuganov, won only about 18 percent of votes, according to exit polls by a state pollster and a polling group that has proved reliable in the past.Nationalist Vladimir Zhirinovsky, ex-parliamentary speaker Sergei Mironov and billionaire Mikhail Prokhorov were all forecast to win less than 10 percent, although Prokhorov won plaudits for a relatively strong campaign.Zyuganov said his party would not recognize the official results and called the election "illegitimate, dishonest and untransparent." Liberal leader Vladimir Ryzhkov also refused to recognize the result.The organizers of the anti-Putin protests, which portray him as an autocratic leader whose return to power will stymie any hope of economic and political reforms in Russia, said they would resume their protests on Monday."The social base of the protest is going to grow and Putin with his team did everything wrong to make this happen. He really helped us," said journalist Sergei Parkhomenko, one of the leaders of the opposition protest movement."He is forcing things to breaking point. He is declaring war on us. As a result the base of aversion to him is growing."