Thousands of demonstrators are outside the Ukrainian parliament shouting "revolution" as the legislature opens a session that could bring a vote of no-confidence in the government.

The parliament is to start its session discussing the violence and chaos of the past several days stemming from massive demonstration denouncing President Viktor Yanukovych's decision to shelve signing an agreement with the European Union deepening economic and political ties. Riot police have reacted harshly against demonstrators several times in previous days, beating some with truncheons.

After the general discussion, the parliament on Tuesday is to consider whether to put an opposition-backed no-confidence motion to a vote.

If it does come to a vote, it is unclear if the opposition has enough support to pass it. Several lawmakers from the governing party have defected.