The opposition has called for a vote of no confidence in the government of Prime Minister Mykola Azarov amid days of mass protests over the abandoning of the historic pact, the biggest protests in the ex-Soviet country since the pro-Western Orange Revolution in 2004.
But it was unclear whether it would muster enough support to pass the motion.
Opposition leaders including former heavyweight world boxing champion Vitali Klitschko have introduced a draft resolution saying that the government had betrayed the Ukrainian people by scrapping plans to sign an Association Agreement with the European Union under pressure from Russia.
Prime Minister Azarov said yesterday that the situation bore all the hallmarks of a coup d'etat, while Russian President Vladimir Putin said that protests "seem more like a pogrom than a revolution."
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The White House weighed in by saying that it did not consider peaceful demonstrations to be a coup.
On today morning, several thousand riot police were deployed all around the parliament building in central Kiev.
The opposition needs to gather 226 votes in the 450-seat parliament, the Verkhovna Rada, to pass a vote of no confidence.
Nikolai Tomenko, a lawmaker from the party of jailed opposition leader Yulia Tymshenko, said yesterday that the opposition could muster only 215 of the necessary votes in the parliament dominated by President Viktor Yanukovych's Regions Party.
Opposition leader Arseny Yatsenyuk told a rally late yesterday: "First we vote for the draft resolution on dismissing the government, then we vote for the release of Tymoshenko and three activists on Independence Square, who were illegally arrested.