Negotiations between opposition and Ukrainian President Viktor Yanukovych failed Thursday after both sides did not come to an agreement.

Ukraine's three main opposition leaders held several hours of talks with Yanukovych but the relatively minor concessions offered by the President were greeted with derision by tens of thousands of protesters on Independence Square in Kiev.

After four hours of talks with Yanukovych the leader of the opposition Fatherland party, Arseniy Yatsenyuk, said there was a high chance of finding a solution to end the bloodshed.

But the boxer-turned politician Vitali Klitschko later said the president appeared to be turning a deaf ear to the opposition's key demand of the resignation of the government.

"I feel how tense the atmosphere is. I feel how great the hopes are. The outcome of the talks is going to disappoint you," he said.

The leader of the nationalist Svoboda party Oleg Tyagnybok specified that the authorities had vowed to release activists arrested during the protests.

Meanwhile, US Vice President Biden called Ukrainian President Viktor Yanukovych to urge an immediate de-escalation in the standoff between protesters and security forces in downtown Kiev, Kyivpost reported.

The Vice President urged President Yanukovych to take steps to end violence and to meaningfully address the legitimate concerns of peaceful protesters, stressing the importance of the ongoing dialogue with the opposition and the need for genuine compromise as the only solution to the crisis.

Tensions have also spiralled outside Kiev and the governor of Ukraine's western Lviv region, Oleg Salo, signed his resignation on Thursday after anti-government protesters shouting "revolution" stormed his offices.

The anti-government movement began in protest at Yanukovych's decision in late November to pull out of a landmark treaty with the EU, but has expanded to demand his resignation.

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