Ukraine's embattled President Viktor Yanukovich has accused the opposition of staging a coup and has refused to give into demands to resign, according to AFP news agency.
I am not leaving the country for anywhere. I do not intend to resign. I am the legitimately elected president
He told local television station on Saturday that "everything happening today can primarily be described as vandalism, banditry and a coup d'etat. That is my assessment".
"I am not leaving the country for anywhere. I do not intend to resign. I am the legitimately elected president," Yanukovich told the television station in the eastern Ukrainian city of Kharkiv.
The embattled leader, who is thought to have travelled to eastern Ukraine, his power base, said he felt that his own security and the safety "of people close to me" was being threatened by protesters who had taken control of large parts of central Kiev after deadly clashes left about 80 dead.
He added that he had been given "security guarantees" by international mediators who helped him and the opposition sign a political pact on Friday aimed at ending the country's three-month crisis.
Earlier on Saturday, an emboldened opposition took control of central Kiev and key government and parliament positions and voted to immediately free jailed opposition leader Yulia Tymoshenko.
Anti-government demonstrators entered Yanukovich's compound in the capital on Saturday and were controlling the entrance, a Reuters news agency journalist at the scene reported.
Key government buildings were without police protection and baton-armed protesters dressed in military fatigues wandered freely across the president's once-fortified compound.
The Ukrainian police appeared to retreat from their entrenched defence of the pro-Russian government by releasing a statement in support of "the people" and "rapid change".
The army followed suit, ruling out any involvement in the current crisis rocking the country.
"The army will in no way become involved in the political conflict," it said in a statement.
"The police is at the service of the people and completely shares its aspirations for rapid changes," the interior ministry said in a statement.
"We pay homage to the dead."
The next test for the police will come on Sunday when a deadline expires for protesters to relinquish public spaces such as Independence Square - the focal point of unrest that Yanukovich sparked in November by ditching an EU agreement in favour of closer ties with old master Moscow.
The Ukrainian protests have escalated into a Cold War-style confrontation pitting attempts by the Kremlin to keep reins on its historic fiefdom and Western efforts to bring the economically struggling nation of 46 million into their fold.
The deal on Friday called for the holding of early presidential elections by December and a forming of a unity government.
But signs of the authorities' slipping grip on power were heightened by a bold push by parliament leaders to force Yanukovich to stand down immediately and to immediately free the jailed Tymoshenko.
The parliament has made several important political appointments - including a new parliamentary speaker, interior minister in charge of the nation's police and a Prosecutor General.
They have also voted to speed up the release of jailed opposition leader Yulia Tymoshenko, who is serving a seven-year jail sentence for "abuse of power".
But there have been conflicting reports regarding her release.
The president's ruling Regions Party that had previously pushed Ukraine closer toward Russia was also standing in disarray Saturday amid mass defections by lawmakers to opposition ranks.
Parliament speaker Volodymyr Rybak resigned in favour of Tymoshenko's right-hand man Oleksandr Turchynov.
Meanwhile, governors and regional legislators from Russian-speaking eastern Ukraine have questioned authority of national parliament, according to AP.