KIEV, Ukraine — Opponents of Ukrainian President Viktor Yanukovych blocked state offices and thousands of demonstrators crowded streets in subzero temperatures to protest his refusal to sign a European Union trade accord.
The opposition demanded early general and presidential elections, Arseniy Yatsenyuk, the head of jailed ex-Premier Yulia Tymoshenko’s party, said here Monday. Clashes in the capital Sunday night left hundreds injured after a crowd angered by an earlier police crackdown seized public buildings during the 10th day of unrest. European Commission President Jose Manual Barroso urged authorities to respect democratic freedoms.
‘‘We need a full reset of power,’’ boxing world champion Vitali Klitschko, who’s also the head of the opposition Udar party, said in Kiev Monday. ‘‘People are on the streets, they’re tired, but it’s getting worse. We have to change the system.’’
In an echo of the Orange Revolution in 2004, emotions are flaring in the debate whether Ukraine should tie its future to Russia or the EU. The two powers are jostling for influence over the ex-Soviet nation of 45 million, an essential transit route for Russia’s gas shipments to Europe.
The protests gripping the country from Lviv to Kharkiv are the biggest political crisis since the events nine years ago, when a group including Tymoshenko overturned a presidential election initially won by Yanukovych.
While the 2004 uprising was peaceful, with hundreds of thousands camping out in freezing winter cold for weeks, protests now are marred with violence. That changes the dynamics, according to Gleb Pavlovsky, president of the Effective Policy Foundation in Moscow.
‘‘Everything changed when the Berkut police unit beat protesters,’’ Pavlovsky said by phone from Moscow Monday. ‘‘For Ukraine, this is an absolutely new phenomenon. It’s a shock.’’
The opposition Sunday announced plans for an ‘‘all- Ukrainian’’ strike, urging people to come to Kiev and take part in the protests. Outdoor markets in Kiev are joining the work stoppage, Tymoshenko’s party said on its website.
‘‘Political developments in Ukraine took on an unexpected character and escalated into an apparent political crisis,’’ Alexander Morozov, Moscow-based chief economist for Russia, the Commonwealth of Independent States and Baltic countries at HSBC Holdings Plc, said in an e-mailed note Monday. ‘‘The president and the government risk losing control over the situation and we expect important political changes to follow shortly.’’
The yield on Ukraine’s 2023 government bonds rose 0.6 percentage point to 10.58 percent, the highest since they began trading on April 17, as of 5:30 p.m. in Kiev. The cost to insure the country’s debt against non-payment using credit-default swaps rose to 1,067 basis points from 986.72 basis points on Nov. 28, leaving the Black Sea state the world’s third-riskiest nation behind Argentina and Venezuela.
The Ukrainian central bank hasn’t imposed any restrictions on the national currency, the hryvnia, said central bank Governor Ihor Sorkin.
Sorkin said the bank will ensure stability on the market and will intervene if needed.
Though reaction in financial markets have been tamer than expected, the nation’s recovery from recession may be be hampered should the crisis continue, London-based Capital Economics said Monday in a report.
‘‘There’s a lot of uncertainty about how events will pan out from here on, but the key point is that a prolonged period of political instability is the last thing Ukraine’s struggling economy needs,’’ Liza Ermolenko, an emerging-markets economist at Capital Economics wrote. ‘‘Protests in Ukraine only add to reasons to be worried about a further deterioration in the economy and the external position.’’
Demonstrators who camped out all night blocking the streets arrived at the cabinet’s building before 6:30 a.m. in Kiev, chanting ‘‘Good morning,’’ according to a broadcast on Channel 5 television.
Protesters also blocked the central bank’s entrance. The mayor’s office was seized Sunday and a group stormed the headquarters of the presidential administration. Across the capital city Monday, groups of protesters sang the national anthem every hour as light snow dusted streets and squares.
At Independence Square, the center of the Orange Revolution, dozens of Ukrainian and EU flags snapped in the breeze, while hundreds of demonstrators attached flags to their clothing and handbags.
With no sign of the protests abating, the Kiev administration issued a storm alert tonight for more wind, snow and rain.
Protests began on Nov. 21 when Yanukovych suspended progress toward an association agreement with the EU, opting instead to strengthen ties with Russia, which supplies 60 percent of Ukraine’s gas. The protests grew over the weekend after the president failed to reconsider the deal at a Nov. 28-29 EU summit in Vilnius and the first clashes broke out.
Russian President Vladimir Putin said last month he doesn’t oppose the EU deal and suggested three-way negotiations. European Commission President Jose Barroso reiterated that the idea of such talks is unacceptable. The two sides accused each other of pressuring the Ukrainian government.
Putin’s government may have offered Ukraine $15 billion in loans, debt restructuring and asset purchases to persuade it not to proceed with the EU deal, the Ukrainian magazine Zerkalo Nedeli said. Azarov also said Sunday on Inter television he wanted to agree a new price of gas in two weeks.
Russia will offer cheaper natural gas to Ukraine if the government in Kiev opts to join the Moscow-led economic bloc, First Deputy Prime Minister Igor Shuvalov said in an interview.
‘‘A gas agreement could help relieve Ukraine of a huge problem,’’ Shuvalov said in comments cleared for publication Nov. 30. ‘‘We can also give them a loan, but we will not help them without commitments on their part.’’
Western leaders stepped up calls for calm as the confrontation intensified Sunday night. NATO Secretary General Anders Fogh Rasmussen urged protesters and police to remain peaceful, according to a statement on the military alliance’s website. U.S. and EU ambassadors to Ukraine did the same.
Yanukovych said Sunday he still favors ‘‘moving toward the EU,’’ as long as that doesn’t hurt the country economically.
‘‘Our country should integrate with the European nations as an equal partner,’’ Yanukovych said in Sunday’s speech to mark the 22nd anniversary of a referendum that clinched Ukraine’s independence after the Soviet Union collapsed in 1991. ‘‘I will not allow any serious economic losses and decline of living standards.’’
_ With assistance from Bryan Bradley in Vilnius and Paul Abelsky, Henry Meyer, Irina Reznik and Scott Rose in Moscow.