Despite freezing conditions protesters have barricaded themselves on Kiev's Independence Square, where they have camped out for three weeks of protests sparked by Yanukovych's refusal to sign an integration deal with the European Union.
But perhaps adding fuel to the country's worst political crisis of a decade, supporters of the president announced they will hold a rally of their own and began to set up dozens of field kitchens not far from the protest camp on Sunday morning.
Ukraine's security services went on high alert, citing the continuing tension in Kiev's city centre and several recent anonymous bomb threats.
Organisers of the pro-government rally plan to bring 200,000 supporters to central Kiev and may stay there indefinitely, said Kiev police spokeswoman Olga Bilyk.
"Policemen will separate the two protests," she said.
On the square, known as the Maidan, several thousand of pro-EU protesters continued to build up the massive barricades overnight and stockpiled food and firewood.
The opposition has decried the rival rally as an artificial creation by Yanukovych's Regions Party that has brought in state employees under threat of firing them and planned to disrupt their three-week-long camp.
'Only forward, to Europe'
Under intense pressure, the Ukrainian leader is running out of time to decide whether to turn his politically volatile nation towards the West by signing a deal with the EU, or join a Moscow-led Customs Union.
As the embattled 63-year-old president hedges his bets, the opposition has called for another monster rally after hundreds of thousands swelled the central square last weekend.
The US State Department warned Washington would be watching the rallies closely, urging Ukraine authorities to steer clear of strong-arm tactics just days after riot police stormed protesters' barricades in a failed bid to reclaim the square.
Protesters have now sealed it with barricades topped with barbed wire and the blue and yellow flags of Ukraine and the EU.
Various celebrities have been keeping the protest mood going, including sports idol and heavyweight champion Wladimir Klitschko, the younger brother of opposition leader and boxing champion Vitali.
"When you have a dream, desire, and potential, you will persevere anything," Klitschko said from the stage late Friday. "Only forward, closer to Europe!"
Govt warned against use of force
Yanukovych on Friday held talks with the three main protest leaders -- leader of the UDAR party Klitschko, nationalist leader Oleg Tyagnybok and the head of the party of jailed opposition leader Yulia Tymoshenko, Arseniy Yatsenyuk.
In a tense encounter, Yanukovych promised amnesty for those arrested during the protests and a "moratorium" on actions by the security forces.
"I address all citizens with a request to calm down and halt confrontation," said Yanukovych.
But the opposition, which has insisted that the government of Prime Minister Mykola Azarov should resign and riot police punished for beating protesters, said Yanukovych's promises were nowhere near enough.
"We heard nothing in response to our demands. We want to see clear steps out of crisis, not to hear calls," said Klitschko.
He warned the president against sending riot police to break up Sunday's protest.
"It will have terrible consequences for the country and for you personally," Klitschko said.
The talks at a concert hall were chaired by post-Soviet Ukraine's first president Leonid Kravchuk and were also attended by top church leaders, parliament speaker, foreign minister and other top figures.
The negotiations came after Ukraine's richest man and hugely influential powerbroker Rinat Akhmetov called on all parties to find a peaceful solution to the crisis.
The United States has made its solidarity with Ukraine's opposition clear, even threatening sanctions after the failed police raid on Wednesday, and outspoken Republican Senator John McCain announced he is heading to Kiev.
Russian Foreign Minister Sergei Lavrov meanwhile accused Western countries of losing "their sense of reality" over Ukraine's crisis and accused them of using blackmail to artificially sever the country from Russia.
