KIEV (Reuters) - Opposition leader Viktor Yanukovich claimed victory in Ukraine’s presidential elections on Sunday and told his bitter rival Yulia Tymoshenko to resign as prime minister, but she refused to concede and declared she was ahead.

Yanukovich, 59, a beefy ex-mechanic who wants better ties with Moscow, promised quick reforms to overcome Ukraine’s deep economic crisis after exit polls and initial results gave him a lead of several points over Tymoshenko.

“I think that Yulia Tymoshenko should prepare to resign. She understands that well,” Yanukovich said in a television interview.

Preliminary official results, with just over 16 percent counted, gave Yanukovich 51.86 percent against 42.80 percent for longtime rival Tymoshenko. Exit polls but him 3-4 points ahead.

But presaging a possible messy legal challenge, Tymoshenko’s campaign chief said her camp was conducting a “parallel count” that gave Tymoshenko the lead with 46.8 percent to 46.0 for Yanukovich with 85 percent of votes counted.

In yet another count, Yanukovich’s camp said he was ahead by 4.5 percent.

Tymoshenko was the co-architect of Ukraine’s 2004 Orange Revolution, when mass street protests overturned an initial Yanukovich election victory tainted by fraud.

Former gas tycoon Tymoshenko, 49, was in no mood to give up this time either. Looking stern before reporters, she urged her team to “fight for every result, every document, every vote.”

Legal challenges and street protests from Tymoshenko could further delay Ukraine’s chances of repaying over $100 billion of foreign debt and nursing its sickly economy back to health after a 15 percent collapse last year.

In Russia, Ukraine’s former Soviet master and the source of the gas which flows through its pipeline network to the West, the election was closely watched but state-controlled media avoided taking sides.

Apparently keen to avoid repeating Moscow’s 2004 gaffe of prematurely congratulating Yanukovich, Kremlin officials said there was unlikely to be any official comment on Sunday night.

ORANGE REVOLUTION BURIED?

Sunday’s vote, conducted in freezing temperatures and snow, appeared to reflect widespread disillusion among Ukrainians that the Orange Revolution failed to deliver prosperity or stability.

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The $120 billion economy has been battered by a decline in the value of Ukraine’s steel and chemicals exports that has hammered the hryvnia currency, slashed budget revenues and undermined the domestic banking system.

President Viktor Yushchenko, the other leader of the Orange Revolution, was eliminated from voting in the first round of the election after coming a humiliating fifth. He launched a series of bitter personal attacks on his former ally Tymoshenko.

Voters were unenthusiastic about either candidate but seemed to feel Yanukovich, a former premier who stressed the fight against poverty, had the best chance of restoring order.

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“We lost five years of our lives thanks to Yushchenko and Tymoshenko,” said Oleg Nochvyn, a miner in his 50s in the eastern region of Donetsk.

“For five years they were promising us -- tomorrow will be better. Well, I get up the next day and it’s worse than the day before ... Under Viktor Fyodorovich (Yanukovich) we had everything -- economic growth, everything was getting better.”

Regardless of the outcome of Sunday’s election, squabbling was set to continue, reflecting the country’s broader divisions. Ukraine is divided almost equally between a Russian-leaning east and south and a Western-friendly center and west.

Assuming Yanukovich’s victory is confirmed, Tymoshenko can expect in any case to be ousted as prime minister by a vote of no confidence in parliament.

Yanukovich will then try to form a new coalition to get his own ally into the role, or call a snap parliamentary election.

Before polls closed, Tymoshenko’s camp complained of multiple voting and bribery in the eastern Donetsk region, the industrial power base of Yanukovich, and said it would contest results in around 1,000 polling stations.

Volodymyr Mayevsky, head of the Interior Ministry’s public security department, told a news conference that voting “got underway smoothly, without blatant violations of public order.”

Investors want a new president who will be able to resume borrowing from the International Monetary Fund (IMF). The IMF put lending on hold in frustration at political squabbling and concerns about budget spending.