( CNN ) -- Ukrainian military forces will not interfere in the current political unrest , a government minister said Sunday , despite ongoing protests and clashes that threaten to bring the eastern European country to a standstill . Opposition leaders have vowed to pursue their demands after rejecting a package of concessions , including government posts , offered by President Viktor Yanukovych . Thousands of protesters have continuously massed in central Kiev -- the power base of the opposition , which seeks the government 's ouster and snap elections -- at times clashing with police . On Sunday , a memorial service was held for a protester was killed in the violence last week . His coffin was carried through snowy Kiev streets amid chants of `` Hero '' and `` He died for us , he died for Ukraine '' from the thousands of people , including protest leaders , who had gathered to pay their respects . Ukraine , a nation of 45 million people , has been thrown into a deepening political crisis after weeks of protests by pro-Europe demonstrators that have escalated into deadly clashes . But Defense Minister Pavel Lebedev said the military would not intervene . `` The army will abide strictly by the constitution and laws of Ukraine that set clearly its role , functions and tasks , including use of armed forces , '' he told Russian state news agency Itar-Tass in an interview on Sunday . Among the snowy rooftops of the capital , Kiev , smoke can often be seen billowing from the center , where thousands of demonstrators have massed despite the freezing temperatures , setting up makeshift barricades and bombarding police with gasoline bombs . Scenes of fires , burnt tires , smashed windows and the drumbeats of sticks on corrugated metal have become familiar occurrences on the city 's central arteries . Offer rejected . On Saturday , opposition demonstrators smashed out windows and doors of a government building in Kiev and used fireworks to smoke out police , according to a journalist at the scene . Opposition leaders said the demonstrators targeted the Ukrainian House because police were launching attacks against them from there . This came after opposition leader Vitali Klitschko rejected concessions from the government . On Saturday , Yanukovych offered government posts to Klitschko and another leader of an opposing party , the presidential website said . Arseniy Yatsenyuk , who heads the Fatherland Party , would have become the prime minister and , under the president 's offer , would have been able to dismiss the current government , which has been one of the protesters ' demands . The president also offered the post of deputy prime minister on humanitarian issues to Klitschko , a former champion boxer known as `` Dr . Ironfist . '' Yanukovych also said he would agree to a working group to look at changes to the constitution , according to the president 's website . However , speaking on a public stage where he was joined by heads of other opposition parties , Klitschko rejected the offers . His announcement was greeted by loud cheers from the crowd . Emboldened , the opposition leaders have said they would press for more concessions -- elections and the abolition of sweeping new anti-protest laws . A special session of parliament is scheduled for Tuesday . Tent cities . The thousands of protesters who have packed Kiev 's central Independence Square and surrounding streets have shown no signs of leaving . They have set up tent cities and put up barricades , outside of which police have massed . The clashes are an escalation of weeks of largely peaceful public protests prompted by Yanukovych 's decision in November to spurn a planned trade deal with the European Union and turn toward Russia instead . More recently , protesters , old and young , have been voicing their anger over new anti-protest laws , passed earlier this month . The controversial new laws have sparked concerns they could be used to put down demonstrations and deny people the right to free speech . Klitschko 's party , the Ukrainian Democratic Alliance for Reforms , warned on Saturday that authorities are preparing to provoke peaceful protesters and may plant provocateurs among the crowds in an effort to enact emergency rule . A group of protesters blocked the entrance to the Energy Ministry on Saturday , a move Energy Minister Eduard Stavytsky called a direct threat to the entire energy system . Some protesters entered the building and argued with Stavytsky . The protesters left the building saying they did not intend to undermine the work of the ministry in any way . Foreign governments have condemned the escalating violence and the European Union is getting involved in the crisis . The EU 's commissioner for enlargement and European neighbourhood policy , Stefan Fule , visited Kiev on Friday and Saturday . Next week , EU foreign policy chief Catherine Ashton and a European Parliament delegation are scheduled to travel to Ukraine . In a statement , Fule said he held talks with Yanukovych and opposition leaders . `` My talks in Kiev showed the need for a series of concrete steps to first start to rebuild trust of people by stopping the spiral of violence and intimidation , to be complemented in a second stage by an inclusive political process leading the stability in Ukraine , '' Fule said . Read more : Is Ukraine becoming a dictatorship ? Read more : Ukraine protests - 5 things you need to know . CNN 's Diana Magnay , Pierre Meilhan , Victoria Butenko and Nana Karikari-apau contributed to this report .
NEW : Memorial service for soldiers killed in clash last week . Defense minister says he will not get involved in political conflict . Opposition leaders demand president 's concessions . Kiev rocked by ongoing clashes between protesters and police .