While some in the crowd waved EU and Ukranian flags in Independence Square, others tore down a statue of Vladimir Lenin, the former leader of the Soviet Union, using metal bars and ropes. They then smashed the statue with hammers as protesters chanted “glory to Ukraine”.
The move came after Russian President Vladimir Putin encouraged Ukraine to instead join a Russian-led customs union.
Both Russian and Ukrainian leaders deny discussing the issue of Kiev joining the customs union along with Belarus and Kazakhstan during their meeting in the Russian city of Sochi on Saturday.
Leaders of the protesters gave Mr Yanukovych a 48 hour ultimatum to dismiss the government and are in the process of setting up barricades outside government offices.
The ongoing protests are the largest seen in the country since the pro-democracy Orange Revolution in 2004.
The European Commission said EU foreign policy chief Catherine Ashton would travel to the state to “support a way out of the political crisis”.
Aside from the protests, the Ukrainian Security Service confirmed an on-going investigation into “actions aimed at seizing state power” but did not name the politicians allegedly involved.
Meanwhile, the Berkut, Ukraine’s special police force, have been criticised for beating protesters on Independence Square, or Maidan.
Undeterred, the opposition party of jailed former Prime Minister Yulia Tymoshenko has urged people to “chase” the president “until he falls”.
“We are on a razor's edge between a final plunge into cruel dictatorship and a return home to the European community,” Mrs Tymoshenko said in a message to the crowd read out by her daughter.
“Don't give in, not a step back, don't give up, the future of Ukraine is in your hands,” he said.