About 100,000 protesters rallied in Kiev and other cities in Ukraine at the urging of jailed opposition leader and ex-Prime Minister Yulia Tymoshenko, who called on Ukrainians from all over the country to gather in Kiev for the demonstration against the government's failure to sign a key trade agreement with the European Union.
"Fly, drive, walk to Kiev from all parts of Ukraine, but gather everyone on Dec. 1," Tymoshenko said in a statement that was read aloud by her daughter Saturday.
The New York Times reported demonstrators clashed with police late Sunday afternoon outside the presidential administration building. About 100 police officers and more than 50 protesters were injured, some reporting chemical burns to their eyes from tear gas, officials said.
In Kiev's Independence Square, protesters broke through metal shields surrounding a big Christmas tree under construction. The climbed the tree and topped it with the Ukrainian flag.
Speakers at the rally in Independence Square included Yuri Lutsenko, a former interior minister and a leader of Ukraine's Orange Revolution in 2004. The Times said Lutsenko told the crowd, "I want the authorities to know that this is not a protest; this is a revolution!"
Protests in Ukraine started more than a week ago after the government announced plans to suspend an EU association trade agreement.
Yanukovych said he was pressured by Russia to back away from the deal and that Ukraine could not afford to lose Russia as an ally.
Kiev's police chief, Valery Koryak, resigned Sunday, apologizing for the use of excessive force Saturday by riot police that resulted in seven people being hospitalized, CNN said.