KIEV (Reuters) - Ukraines opposition leader Viktor Yanukovich has narrowly won Sundays presidential election against Prime Minister Yulia Tymoshenko, exit polls said. The National Exit Poll, a consortium partly funded by western embassies, said opposition leader Yanukovich had secured 48.7 percent of the vote against Tymoshenkos 45.5 percent. Another exit poll, by ICTV, said he won 49.8 percent of the vote against her 45.2 percent. The victory by Yanukovich, if confirmed by official results, marks a remarkable comeback by the 59-year-old ex-mechanic who was disgraced in 2004 by the Orange Revolution mass street protests which Tymo-shenko led. But the closeness of the result, indicated by the exit polls, suggested that Tymoshenko might contest the outcome. She threatened last week to call people out on to the streets if there was any evidence of fraud. Yanukovichs election in 2004 in a poll deemed to have been rigged was quashed by a court and he lost a third round of voting to his rival, the pro-Western President Viktor Yushchenko. Sundays runoff vote in the ex-Soviet republic of 46 million people climaxed a bitter campaign of smears and insults exchanged between Yanu-kovich and Tymoshenko. The fiery, sharp-tongued Tymoshenko branded him a puppet of wealthy industrialists in the east of the country whose business interests he represents. She also denounced him a coward for refusing to face her in a pre-election TV debate. He accused her of making outlandish promises that she could not keep and telling beautiful lies. His election is certain to lead to a warming of ties with former imperial master Russia. These plunged into a deep chill under Yushchenko because of the latters strong Ukrainian nationalist line and his bid to take Ukraine into NATO. Yanukovich has spoken out against NATO membership and, at a meeting with the newly-appointed Russian ambassador on Friday, said that Ukraine, under him, would turn a new page and re-establish traditional warm relations with its big neighbor. He has, like Tymoshenko, also pledged to work to integrate Ukraine in Europe though he has not spelled out detail. He built a campaign around helping to defeat poverty in his country and his main task will be to get the struggling economy, hard hit by the global downturn, back on to its feet. He has said he is ready to begin talking to the International Monetary Fund which suspended disbursement of its $16.4 billion bail-out programme late last year because Ukraine breached pledges. But he supports higher social spending in the country which runs counter to IMF calls for fiscal restraint. Meanwhile, a top aide to Prime Minister Yulia Tymoshenko said on Sunday that it is too early to declare the winner in Ukraines presidential election and extensive fraud has taken place. It is too early to declare a winner, Deputy Prime Minister Olexander Turchynov said in televised remarks. We could not avoid extensive falsifications, he added, speaking after the release of exit polls showing that Tymoshenko had lost by between three and five percentage points to her pro-Russia rival, Viktor Yanukovich.