The demonstrators camped out at the central square on Sunday night. They demand early parliamentary and presidential elections, as well as resignation of President Viktor Yanukovych.
The demonstrators say they will not leave the square “until the government resigns.”
Earlier in the day, some 100 police officers and nearly 50 protesters were injured in clashes as demonstrators stormed the office of Kiev’s mayor.
Protesters also used a bulldozer to break through a barricade near the presidential compound in the capital.
The Independence Square demonstration follows a week of public protests in Kiev.
The Ukrainian president has refused to sign a political and trade agreement with the European Union. The refusal sparked public anger among pro-Westerners.
The EU signed an Association Agreement with Moldova and Georgia at the end of the third Eastern Partnership Summit in the Lithuanian capital, Vilnius, on November 29.
Ukraine refrained from signing the agreement after the EU leaders said that Kiev had to allow imprisoned former Prime Minister Yulia Tymoshenko to travel overseas for medical treatment. Tymoshenko has called a general strike to be held in a bid to force the resignation of Yanukovich’s government,
European Union (EU) leaders have blamed Russia for Ukraine’s refusal to sign the trade deal with the bloc. European Commission President Jose Manuel Barroso has said Brussels would not allow Russia to “veto” deals with Ukraine and other Eastern European countries.
Yanukovych, has defended his decision to scrap the signing, saying that Kiev needs economic and financial support from the 28-nation bloc before it could sign the accord.
The Ukrainian president, however, said on Friday, “I confirm Ukraine’s intention to sign the Association Agreement in the near future.”
Kiev argues that Ukraine cannot afford to sacrifice trade with Russia for closer ties with the European Union.