Emotional crowds on Kiev's Independence Square rounded on opposition leaders after they signed an agreement with President Viktor Yanukovich to end a protracted crisis, and said they would not wait any longer for him to go.
Passions ran high as the coffin of a victim from Thursday's violence, when dozens were killed during anti-government protests, was borne through the crowd to the stage on the square, apparently catching opposition leaders off guard.
Despite the deal signed by Yanukovich and the opposition, many on the square were in no mood to call off the protests which erupted in November after the president abandoned a trade pact with the European Union and turned instead towards Moscow.
After another open coffin was held aloft by the crowd, a protester wearing battle-fatigues leapt up to the microphone and triggered roars of approval as he declared: "By tomorrow we want him (Yanukovich) out!"
Referring to the three opposition leaders, including boxer-turned-politician Vitaly Klitschko, who were standing behind him, the man said: "My comrade was shot and our leaders shake the hand of a murderer. It's a disgrace."
"We have given you politicians a chance to become ministers in the future, even the president, but you don't want to fulfil our one demand - that this criminal leave office."
"We, simple people, are telling the politicians behind our back, that there is no way Yanukovich will be president for the whole year. He has to be gone by 10 a.m. tomorrow."
"If it is not announced by 10 tomorrow that Yanukovich is gone, we're going to attack with weapons," he said.
Earlier Klitschko drew cat-calls and derisive whistling from the crowd when he had praised as "very important" their political achievements during the day.
Klitschko and his fellow opposition leaders, Arseny Yatsenyuk and nationalist Oleh Tyanibok, earlier signed an EU-brokered deal with Yanukovich in which Yanukovich made important concessions after two and a half months of confrontation on the streets of Kiev.
These included early elections, formation of an interim government and a return to an earlier constitution which will mean him giving up key powers, including control over the make-up of the government.
Klitschko later apologised for shaking Yanukovich's hand, taking the microphone and telling the crowd: "If I offended anyone, I ask their forgiveness."
But many among the protesters were firm in their rejection of the accord.
"I'm going to fight until the death," said Vasily Stefinyuk, a 50-year-old veteran of the Soviet invasion of Afghanistan from the northeastern city of Kharkiv.
"We've been betrayed," he said. "We're not here because of Klitschko or Yatsenyuk, we're here to get rid of Yanukovich."
Another man, 35-year-old Volodymir from the western city of Lviv near the Polish border, said: "We won't follow Klitschko and the rest of them. They shook hands with a gangster and danced with the devil."
