Clashes have erupted outside city hall in the Ukrainian capital Kiev on Wednesday as police try to oust occupying protesters.
The action follows a night of scuffles and a stand-off after police moved in on the protest camp in Independence Square.
More demonstrators have joined the protest in response to an opposition call for solidarity the BBC reports.
The government's decision to withdraw from a free-trade deal with the European Union in November sparked huge street rallies.
Police stormed city hall as they tried to dislodge protesters from the building. Reports said protesters used hoses to fire icy water back at officers.
Police had moved about 2am on Wednesday (local time), saying they wanted to free up a passage through the square for traffic.
Protesters in hard hats locked arms to form human walls to try to resist the police push. At least nine people have been detained.
On Tuesday, EU foreign policy chief Catherine Ashton held talks with President Viktor Yanukovych.
Baroness Ashton, who was cheered by crowds when she visited Kiev's main protest site, said she was saddened that police had later used force to try to remove protesters.