Turbulence in the east has triggered violence in Ukraine’s parliament which has passed a law envisaging long jail terms for acts against the country’s territorial integrity.
But as Kyiv moved to assert its authority, communist leader Petro Symonenko told the chamber that demonstrators’ demands should be listened to.
“You are today doing everything to intimidate people. You arrest people, start fighting people who have a different point of view,” he said.
He also accused nationalists of setting a precedent by seizing public buildings when they had protested against the rule of now ousted President Viktor Yanukovych.
Two members from the Svoboda far-right party took exception to the charges and seized Symonenko at the rostrum. Supporters rallied to his defence and a brawl broke out with deputies from other parties joining in and trading punches.
It comes as a war of words continues between Moscow and the West.
NATO warned Moscow on Tuesday of “grave consequences” to its relationship with the West if it intervened further in Ukraine.
But Russian Foreign Minister Sergei Lavrov dismissed
US accusations that Moscow was destabilising Ukraine, saying the situation could improve only if the interests of Russian speakers were taken into account.