Ukrainian protesters declared a general strike and blockaded government buildings Monday after violent clashes in which more than 100,000 sought early elections over the authorities' rejection of a historic EU pact.
Nearly 10,000 supporters of the ex-Soviet state's alliance with the European Union and disavowal of old master Russia camped out overnight on Kiev's iconic Independence Square in a bid to keep alive Ukraine's biggest pro-democracy protest since the 2004 Orange Revolution.
Thousands then moved toward government and state administration buildings calling for President Viktor Yanukovych's immediate ouster and a nationwide strike.
Streams of cars honked their horns in support while church bells rang out across the heart of the ancient capital in scenes posing the single biggest challenge to the president's three-year rule.
"We are tired of these gangsters and bandits," said a driver who identified himself as Ivan Filipovich after pulling his car alongside others blocking the entrance to the main government building.
"Everything is corrupt. We want to be close to normal countries and not Russia," the 51-year-old said while glancing at the gold-and-blue flag of the European Union hanging out his window.
The swarming crowd had first defied a ban on protests on Sunday by driving lines of helmeted police off the same expansive square that provided the setting of the dramatic 2004 revolt.
Some of the more militant in the group also steered a bulldozer within striking distance of barricades protecting the Yanukovych administration building.
Security forces outside the president's seat of power fired dozens of stun grenades and smoke bombs at masked demonstrators who were pelting police with stones and Molotov cocktails.
Kiev's city government said in an update Monday that 165 police officers and demonstrators had been injured in the most serious clashes witnessed in Ukraine since the Soviet Union's demise.
The economically struggling nation of 46 million was thrown into crisis when Yanukovych snubbed EU leaders at a summit on Friday and refused a deal that would have paved Ukraine's way to eventual membership in the 28-nation bloc.
EU leaders primarily blamed the decision on the stinging economic punishments Russia had mooted should Ukraine take the fateful step toward the West.
Yet the move now threatens to backfire on Yanukovych as his political foes try to build momentum amid discontent with state corruption and disappearing jobs.
About 50,000 protesters also rallied on Sunday in the Ukrainian-speaking western city of Lviv. Another 250 EU supporters ignored a court ban in Yanukovych's native region of Donetsk.
The weekend violence drew a call for restraint from the US State Department as well as Polish Foreign Minister Radek Sikorski and his Swedish counterpart Carl Bildt, two leaders spearheading the EU's expansion east.
Ukrainian officials were dealt more embarrassment Monday when members of the nationalist Svoboda party held on to their control of Kiev city hall after storming the empty building late Sunday.
"A revolution is starting in Ukraine," Svoboda party chief Oleh Tyahnybok declared.
"We are launching a national strike," he said in a call supported by other opposition leaders.
It was not immediately clear how many Ukrainian workers had in fact downed their tools and the action at first appeared to be largely symbolic.
But local authorities in several western cities had either joined calls for a general walkout or had simply refused to show up at work.
Ivano-Frankivsk city mayor Viktor Anushkevichus said in a statement that he and his deputies were taking an unpaid leave of absence "in solidarity with the strikers".
City officials in Lviv also issued a statement supporting the action.
Yanukovych appeared to be trying to diffuse the standoff by affirming Sunday that Ukraine had already chosen its "historic path" by committing itself to closer EU ties.
Yet he also stressed those relations would come only when Kiev was treated as "an equal partner that is respected and whose wishes are taken into account".
Ukraine's nuanced approach in which it seeks favour from both Moscow and Brussels was underscored yet again when the government said Yanukovych would travel to Russia to sign a new "cooperation roadmap" after completing a visit to China on Friday.
Russian Foreign Minister Sergei Lavrov was also due to meet Ukrainian officials in Kiev when he attends an Organisation for the Security and Co-operation in Europe (OSCE) meeting scheduled for Thursday.