In the final hours of the Ukraine’s bitterly fought presidential campaign, candidates accused one another of planning to commit campaign fraud and experts warned of the possibility of post-election unrest.

But among many Ukrainian voters, the no-holds barred campaign may have inspired as much apathy as outrage and some observers were predicting a relatively smooth first-round vote Sunday.

Prime minister Yulia Tymoshenko, who helped lead the 2004 Orange Revolution, has accused front-runner Viktor Yanukovych and his Party of Regions of planning a campaign of voter fraud through falsified absentee ballots and other methods.

”Yanukovych and the Party of Regions are preparing a large-scale falsification in Ukraine,” Tymoshenko said, speaking to the media Thursday. ”For this purpose, they have formed on a corrupt basis a puppet majority in the Central Election Commission.”

Most polls show Tymoshenko running second behind Yanukovych in the race. If no candidate gets more than 50 percent of the vote Sunday, as expected, there will be a runoff between the two top vote getters sometime in February.

Sergei Markov, a member of the Russian parliament and an election observer, said Tymoshenko’s fraud charges are part of an effort to prepare her supporters to challenge a Yanukovych victory.

”Claims that the opposition is trying to rig the vote show that the other side is ideologically preparing to reject the election in case they lose,” said Markov, whose views on many issues are thought to reflect the thinking of the Kremlin. He spoke at the expert panel Friday.

Yanukovych meanwhile has warned that his supporters will not allow any candidate to steal the current presidential contest, as he claims happened in 2004.

The pro-Russian candidate’s initial victory in that race was thrown out by the Supreme Court following the Orange street protests and accusations of widespread fraud by authorities on Yanukovych’s behalf.

”No such scenario will be allowed,” Yanukovych told reporters during a campaign trip to eastern Ukraine Thursday, referring to the street rallies that helped reverse his victory. ”If anybody is hoping for that, we will disappoint them.”

Yanukovych noted that in 2004 he called off plans for mass demonstrations by his supporters in the capital to avoid clashes with Orange protesters. He suggested that this time, his partisans would not back down against those who challenge a Yanukovych victory.

Vladimir Fesenko, the head of Ukraine’s Penta Center for Applied Political Research, predicted that neither Tymoshenko nor Yanukovych would accept defeat in the runoff, which is expected to pit the two old adversaries against one another.

Instead, he said, they would challenge any defeat with peaceful protests. But he warned that if Tymoshenko’s and Yanukovych’s demonstrators face off, it could escalate into violence.

”Neither wants a real war,” Fesenko said. ”But unfortunately there are risks. Often it is difficult to control people once they’re on the streets. There could be adventurists from either camp that could provoke a clash.”

Authorities say they are planning to deploy thousands of police Sunday to ensure an orderly first round ballot.

Foes of Prime Minister Yulia Tymoshenko released a tape this week of a purported conversation between her and Georgian President Mikhail Saakashvili, in which he supposedly says he is sending 2,000 ”battle-ready” observers to monitor the race.

”No worries, we are sending the best prepared and most battle-ready people to you,” the voice alleged to be Saakashvili’s says on the tape, which was played Friday at a panel of analysts and sociologists.

Some here interpreted Saakashvili’s purported comment as a pledge to support Tymoshenko in post-election street protests. Spokespeople for both Tymoshenko and Saakashvili declined to comment, and the authenticity of the tape could not be determined.

Evgeny Kopatko, chief sociologist at Ukraine’s R&B Group, a consultancy, said Friday that if tensions rise after the election, that ”could split the country in two, and this is a very serious risk, economically and politically. The country would be virtually uncontrollable.”

Parliament speaker Vladimir Litvin on Friday appealed to supporters of Ukraine’s rival political leaders, urging not to take to the streets as they did in 2004.

”Today I’m calling on all of the politicians not to deal in actions on the Maidan,” Litvin said, referring to Kiev’s central square where tens of thousands rallied every day for weeks in late 2004.

President Viktor Yushchenko, the eventual winner in 2004, is standing for re-election, but his popularity has plunged and his chances look slim. He warned that the elections could usher in an authoritarian government.

”Should there be an authoritarian regime of either Yanukovych or Tymoshenko, with the criminal elements that will come along, it will take away the freedom of expression,” he said.

Five years after the Orange Revolution brought tens of thousands of people to the streets of the capital, public cynicism appeared widespread. Voters have offered to sell their votes on Web sites for the equivalent of between about $10 and $100.

Despite the dire warnings, Alcee Hastings, a U.S. congressman who is deputy head of the international observer mission, told reporters Friday that so far no one has come up with evidence of intended voting irregularities.

”While the candidates accuse each other of fraud, neither of them has presented you in the media with a smoking gun,” he said. ”I don’t think there’s going to be widespread fraud.”

Hastings noted that the election will come under intense scrutiny. He said there are more international observers in Ukraine for the presidential contest than for any previous election in the former Soviet Union.

But Hastings did not rule out isolated efforts to falsify votes.

”Remember, I’m from Florida, the land of the hanging chads and the butterfly ballots,” he said, referring to the disputed 2000 U.S. presidential contest and the controversial Florida vote count.