Sparking a heated controversy, Greek left-wing leader Alexis Tsipras was sworn in on Monday as the prime minister of a new hardline, anti-bailout government determined to face down international lenders and end nearly five years of tough economic measures, while the EU issued a stern warning to Greece that its place in the eurozone is at risk if Tsipras fails to meet the country's austerity and debt commitments. The decisive victory by Tsipras' Syriza in Sunday's snap election reignites fears of new financial troubles in the country that set off the regional crisis in 2009. It is also the first time a member of the 19-nation euro zone will be led by parties rejecting German-backed austerity. Tsipras' success is also likely to empower Europe's fringe parties, including other anti-austerity movements across the region's economically-depressed south. The trouncing of the conservatives represents a defeat of Europe's middle-ground political guard, which has dallied on a growth-versus-budget discipline debate for five years while voters suffered. "We have an uphill road ahead," Tsipras told President Karolos Papoulias just before being sworn in as prime minister in a ceremony that eschewed the traditional oath on a Bible and blessing with basil and water. Tsipras met Greece's Archbishop Ieronymos to say he planned to take a non-religious oath. Within hours of victory on a campaign of "Hope is coming!", the 40-year-old Tsipras sealed a coalition deal with the small Independent Greeks party which also opposes Greece's EU/IMF aid programme though the two parties are at odds on many social issues like illegal immigration. Syriza won 149 seats in the 300-seat parliament, leaving it just two seats short of an outright majority and in need of a coalition partner. The Independent Greeks won 13 seats. The alliance is an unusual one between parties on the opposite end of the political spectrum brought together by a mutual hatred of the 240-billion-euro bailout programme keeping Greece afloat at the price of budget cuts. The alliance suggests a hardline stance against Greece's creditors, who have dismissed Tsipras's demands for a debt writeoff and insisted the country stay on the path of reforms and austerity to get its finances back on track. But after the euphoria of election night Tsipras faces daunting challenges and can expect strong resistance to his demands from Germany in particular. A series of European policymakers urged Syriza not to renege on commitments. "There is no room for unilateral action in Europe," ECB Executive Board member Benoit Coeure told Europe 1 radio," saying it was important to play by the "European rules of the game". From Brussels to Berlin officials said they were ready to talk to the new government led by Tsipras' radical left party Syriza, but insisted that Athens must stick to prior agreements with its international creditors. Eurozone finance ministers were meeting in Brussels a day after Syriza stormed to victory in elections on the back of Tsipras' promises to end "disastrous austerity" and seek a cancellation of Greek debt. "Membership of the eurozone means that you comply with everything you have agreed with," said Eurogroup head Jeroen Dijsselbloem, adding that "on that basis, we're ready to work with them." The Dutch finance minister did not rule out steps to help Greece -- such as extending debt repayment deadlines or reducing interest rates -- so long as the new government stuck to the austerity measures it has agreed with the EU and IMF since 2010. But he dismissed suggestions that the EU could erase some of the debts that Greece incurred under the massive 240-billion-euro ($269 billion) international bailouts it received, as Tsipras has demanded. "Writing off debt in nominal value, I don't think there's a lot of support for that within the eurozone," Dijsselbloem said. Syriza's stunning victory also has political implications beyond Greece, boosting anti-austerity movements across Europe, especially Spain's Podemos which is hoping for a similar general election win this year. In Germany -- the paymaster of the eurozone bailouts and where resistance runs deep to any attempts to abandon austerity -- Chancellor Angela Merkel's spokesman took a similar line on what Europe expected. "In our view it is important for the new government to take action to foster Greece's continued economic recovery," spokesman Steffen Seibert told reporters. "That also means Greece sticking to its previous commitments." Hawkish Finland also ruled out any write-off of Greek debt. "Finland will not accept a demand for debt cancellation," Prime Minister Alex Stubb said. European Commission chief Jean-Claude Juncker said that the EU would "work closely" with Greece, adding that he was not "particularly nervous". Spanish Finance Minister Luis de Guindos meanwhile insisted that Greece's debt was "not that high". Despite the rhetoric, Brussels is nevertheless set for a "tense" few weeks to come in its negotiations with Athens, a top European official said on condition of anonymity. Tsipras is set to meet other European leaders for the first time as prime minister at a summit on February 12, when Greece's fate in the euro and unsustainable debt levels are sure to be key issues. victory could have wider European repercussions.