In the Ukrainian capital, Kiev, protesters blockaded the main government building on Monday.
The opposition has called for a general strike to bring down President Viktor Yanukovich.
As many as 350,000 of their supporters demonstrated over the weekend.
Many are now camped out in Independence Square.
(SOUNDBITE) (Ukrainian) KIEV PROTESTER, NIKOLAI KOVALENKO, SAYING:
"I'll stay until the end. I have nothing to lose. I have a granddaughter, I have adult children - at least let them have a good life."
Protesters are angry over the government's decision to abandon an EU integration deal.
The former Soviet bloc nation chose to forge closer ties with Russia, instead.
The decision stirred deep passions in a country where many want to escape Moscow's orbit.
The opposition wants the government gone, says this former Interior Minister-turned activist.
(SOUNDBITE) (Ukrainian) FORMER UKRAINIAN INTERIOR MINISTER, YURI LUTSENKO, SAYING:
"The Cabinet of Ministers must go away, and a new life, as well as an economic life, must start"
Under pressure from the opposition, parliament will consider on Tuesday calls for the government's resignation.
President Yanukovich's office said his administration was working normally, despite the blockade, but declined to say where he was.