In Moscow, President Vladimir Putin stated that Russia has not meddled in the affairs of ex-Soviet republics — in a reference to Ukraine — but accused other nations of having done so.
"We haven't engaged in any behind-the-scenes policy-making on the post-Soviet space, and that, to some extent, limits instruments we can use to defend our interests ... unlike our partners which have used them actively," Putin told the State Council, made up of Cabinet members and provincial governors, on Friday.
Putin's blatant support of Yushchenko's rival, Ukrainian Prime Minister Viktor Yanukovych, strained the Russian leaders' relations with the West. Putin has since said he is ready to work with Yuschenko if he wins.
In Kiev, rumors swirled Friday that Cossacks and miners from mainly Russian-speaking eastern Ukraine are readying to disrupt Sunday's vote or head to Kiev in case of a Yushchenko victory.
Campaign officials for Yanukovych, who draws most of his support from eastern Ukraine, have repeatedly denied the allegations. Law enforcement officials have said they would maintain law and order during the rerun.
Yanukovych claimed victory in the Nov. 21 runoff but suspicions of vote-rigging brought tens of thousands of Yushchenko supporters into the streets of Kiev for days of protests. The Supreme Court annulled the results, citing fraud, and ordered a revote.
At a news conference in Kiev, Yushchenko acknowledged being worried about rumors that the runoff might be disrupted, calling it a "working possibility." He warned the outgoing government it would be making a grave error if it allowed any violence.
"I think it will be a colossal mistake on the part of the current regime if even one drop of blood is shed in the coming days," Yushchenko said.
Outgoing President Leonid Kuchma — who has largely abandoned Yanukovych, his former protege — accused both candidates of turning the campaign bitter.
"Both sides succumbed to the temptation to attribute to oneself only glory and to accuse one's political rival of all sins, both unintentional and fictitious," Kuchma said in a televised address.
"We must prove to ourselves and to the world that we are able honestly and without fear elect the person whom we consider the best despite any pressure," he said.
Ukrainian law requires all campaigning to end at midnight Friday so both sides rushed to spread their message.
About 10,000 Yanukovych supporters rallied in Kiev's Victory Square, chanting "Ya-nu-ko-vych! Ya-nu-ko-vych!"
"Together, we will be victorious," Yanukovych told the cheering crowd.
At a later rally in the western city of Uzhhorod, he told supporters: "I believe the Ukrainian people will choose freedom. The Ukrainian people will be the masters of their land. I want my children and grandchildren to live in an independent country."
Anatoliy Zaverenya, 43, said he came to Kiev from the eastern city of Luhansk not so much to support Yanukovych as to defend Ukraine. "If Yushchenko wins, Ukraine will be sold to the west, to the U.S., to Americans," he said.
Olha Karatochko, 67, of Kiev, called Yanukovych "a guarantee of stability and peace in Ukraine"
Meanwhile, a pro-Yushchenko convoy headed to Kiev after traveling through eastern Ukraine.
About 40 cars joined the journey to spread support for Yushchenko, but repeatedly faced roadblocks erected by Yanukovych's backers. Their numbers were expected to swell after entering Kiev, which overwhelmingly backed Yushchenko.
State Security Service chief Ihor Smeshko said law enforcement agencies would maintain law and order Sunday.
The bitter election campaign has underscored stark differences between Ukraine's pro-Yanukovych Russian-speaking east and the western and central regions from which Yushchenko draws his support. Some eastern regions have said they might pursue autonomy if Western-backed Yushchenko wins.
Yushchenko said Friday that if he wins, healing the country will be a top priority.
"The division between ... east and west is something very artificial," he said, accusing authorities loyal to Kuchma of failing to promote dialogue between the mainly rural western regions and the heavily industrialized east.