Ukraine's Prime Minister Mykola Azarov has warned that the anti-government demonstrations in the capital Kiev are becoming "out of control" and could turn into a coup.
Azarov issued the statement as the parliament votes on Tuesday on a no confidence motion against his government.
Al Jazeera's Rory Challands, reporting from Kiev, said that the ongoing debate inside the parliament has broken into "shouting and shoving" between administration and opposition politicians.
"There's a fair amount of chaos inside the parliament," Challands said.
Opposition members shouted "shame" and "revolution" as pro-government lawmakers spoke, while opposition speakers drew boos and jeer.
Outside, demonstrations are continuing and crowds are now blockading the main government buildings, in an ongoing standoff after President Viktor Yanukovych failed to sign a key EU pact.
"Blocking the work of state institutions is not a peaceful demonstration. This has all the signs of a coup," Azarov told ambassadors from the European Union, Canada, and the United States. "That is very serious."
Over the weekend, police forced the protesters off the square, causing injuries to nearly 200 people, including journalists.
The crackdown led to a horrified reaction in the West and the demand by current EU chair Lithuania to launch a probe.
Azarov said Ukraine's authorities were "ready for dialogue" with the protesters and promised that violence would not be used against peaceful demonstrators.
"The authorities are guaranteeing non-use of force against peaceful protesters," he said.
As the demonstration rages, Yanukovych is set to travel to China, leaving the country plunged into crisis by his decision to spurn a landmark EU deal, and boost ties with Ukraine's Soviet ally Russia.
Our correspondent said Yanukovych's decision to leave for China is seen as "running away from the country at a time when he should be here."