Deep freeze fails to deter pro-West demonstrators in Kiev, Ukraine Police refrain from violence after urging from U.S. Vice President Joe Biden Masked men raid opposition party's headquarters, its leader says EU foreign policy chief Catherine Ashton travels to Ukraine on Tuesday The split between loyalties to Russia and the West runs deep in Ukraine Kiev, Ukraine (CNN) -- Arctic temperatures are not enough to cool pro-Western demonstrators' anger at Ukraine's pro-Russian President. Thousands of them refused to budge from Kiev's snow-covered streets Tuesday, while the European Union's top diplomat made her way there to try to thaw the tensions. Security forces in riot gear tried to herd demonstrators away from government buildings, but they refrained from a hard-nosed crackdown. That could be the result of pressure the West has put on President Viktor Yanukovych in the past two days. U.S. Vice President Joe Biden called Yanukovych on Monday to urge him to talk with his opposition and avoid violence. European Commission President Jose Manuel Barroso had phoned on Sunday and also activated EU foreign policy chief Catherine Ashton to fly Kiev to try to work things out. U.N. Secretary-General Ban Ki-moon also called Yanukovych on Sunday to ask him not to use brute force against protesters. Civil disobedience It all started out as a beef between Ukrainians longing to move closer to the West and their Russian-allied President over his refusal to sign an agreement that would strengthen cooperation with the European Union. But then baton-wielding officers triggered sympathies for battered protesters, causing more people to join the demonstrators' ranks in Independence Square and pack inner city avenues with a show of civil disobedience. It became reminiscent of the uprising that swept Yanukovich out of office nine years ago during the Orange Revolution, when he was Prime Minister. The tensions between those who yearn to reap the benefits of an alliance with the West and those who want to stick close by Moscow are longstanding and would seem to be almost irreconcilable. They split the nation geographically between its western regions, where resentment of past Russian domination is higher, and its East, which was settled by Russians centuries ago. Russians make up the Ukraine's largest ethnic minority group, and Russian is widely spoken across the country. Masked raid Monday was tenser, as police broke down barricades protesters had erected after progressing to the presidential administration building. Security forces pushed them back toward Independence Square. Minor scuffles broke out, injuring 10 demonstrators, according to the opposition party. Two policemen were injured, state media reported. Masked men ransacked opposition party's headquarters in a raid, party leader Arseniy Yatsenyuk said. The men, whom he accused of being special forces officers, destroyed the his party's server room, Yatsenyuk said. Equipment was destroyed, dragged out, across the entire premise of the Batkivshina Political Party headquarters, he said Police denied any involvement in the raid. At the same time, Yanukovych appeared to offer an olive branch. He would back a call for talks with his opponents to work out a compromise, an announcement on his website said. Celebs, burning tires Faced with low temperatures near zero degrees Fahrenheit, the protesters burned tires and sipped hot soup and tea to stay warm. Some played soccer or strummed guitars as they camped out in tents. As more police gathered on the streets, the demonstrators received a message of support from two celebrities, one of them actor George Clooney. "We here in the United States have great affinity for those seeking democracy," Clooney said in a video posted online. We learned through trial and error that true democracy cannot exist without a free and fair and honest election. The actor, who has lent his voice to campaigns for various issues in the past, added: "Let me just say this to all of you in the square in Kiev or all around Ukraine: When you look to the West, know that we are looking back at you with great admiration." Former heavyweight boxing champion Ukrainian Vitaly Klitschko, who is famous throughout Europe, is also an opposition leader. He chatted with riot police, urging them to stay calm and "not break the law" should they be ordered to remove protesters. "None of us has either guns nor other objects; this is a peaceful protest," he said. East vs. West Yanukovych's refusal to sign the EU deal represents a U-turn in the country's advance towards closer relations with the West. An EU agreement would have opened borders to trade and set the stage for modernization and inclusion, protesters say. They accuse Yanukovych, who met Russian President Vladimir Putin on Friday, of preparing to take the country into a Moscow-led customs union. Moscow has leverage that may have affected Yanukovych 's decision to backpedal on the EU talks. Russia supplies Ukraine with natural gas, which is essential to keep people from freezing in the country's brutal winters. Moscow can hike Ukraine's energy bills and impose other trade sanctions. The EU is also pressuring Yanukovych to free his chief political opponent Yulia Tymoshenko, who has languished in jailed for two years after being convicted for abuse of power in 2011. The verdict was decried by the EU and other critics as a sham. The Orange Revolution that swept Yanukovych from office in 2004, when he was Prime Minister, also brought pro-Western Tymoshenko to power. READ: The battle over Ukraine: Toward a new geopolitical game Journalist Victoria Butenko reported from Kiev and CNN's Marie-Louise Gumuchian reported and wrote from London.