The Ukrainian capital, Kiev, was rocked by fresh violence on Tuesday.
It was the worst street violence in more than three weeks, as political tension in this former Soviet republic deepened.
Scores of protesters and policemen were injured. There were unconfirmed reports of at least one person dead.
Several thousand-anti-government protesters clashed with riot police near parliament.
They were demanding President Yanukovich relinquish what they said were his "dictatorial powers."
A smaller group peeled away and ransacked his party headquarters.
Opposition leader Vitaly Klischenko called on President Yanukovich to call off his riot police and announce early elections.
(SOUNDBITE) (Ukrainian) UKRAINIAN OPPOSITION LEADER, VITALY KLITSCHKO, SAYING:
"Do this - and this will be a way out."
The mass protests in Ukraine began in November over Yanukovich's decision to forge closer ties with Russia instead of the European Union.
They've
