Talks between European Union country leaders on energy policy ended with no agreement on Thursday, as states squabbled over how to respond to record-high carbon prices and upcoming green investment rules. EU country leaders met in Brussels for a summit to discuss several issues, including soaring energy prices, but some member states - notably Poland - pushed the EU to curb volatile prices in the carbon market by limiting speculative activity, a stance at odds with that of other countries, including Germany. Another squabble emerged over whether the EU should label gas and nuclear energy as climate-friendly investments, with some states seeking to hurry the European Commission into proposing this month the rules on its "sustainable finance taxonomy", a policy that has become the focus of intense lobbying from governments. The talks broke up with no agreement on any energy issues, after leaders could not agree on a final text. "We have realized that there were divergent opinions around the table and we were unable to reach agreement on the conclusions presented," said EU summit chair Charles Michel. He said leaders would discuss the issue again at a future meeting. Polish Prime Minister Mateusz Morawiecki criticised fluctuating CO2 prices, which he said benefited mainly speculators. "ETS prices should be fairly constant and reasonably predictable, not in spikes," Morawiecki said, adding that Poland had proposed changes regarding the carbon market to the European Commission. Europe"s benchmark carbon price soared to a record high of 90.75 euros per tonne last week, having increased by more than 50% since the start of November amid rising gas prices and the looming expiry of ETS options. The CO2 price started the year at roughly 31 euros per tonne. A late draft of the summit conclusions had asked the European Commission to deepen its monitoring of EU ETS trading, including possible speculation by financial intermediaries. Spain has also called for speculative activity to be restricted in recent months. Another attempt at a deal in the energy talks would have asked Brussels to decide whether to label gas and nuclear energy as climate-friendly investments by the end of this month. The Commission has said it plans to propose the rules this month, but has struggled to resolve infighting between countries that disagree on which fuels deserve a "green" label. The carbon market is the EU"s core policy for cutting greenhouse gas emissions causing climate change. It forces power plants and factories to buy a permit for each tonne of CO2 they emit, and the Commission has proposed expanding the scheme to cover shipping and impose higher CO2 costs on airlines. Reporting by Kate Abnett, Jan Strupczewski; editing by John Chalmers and Sonya Hepinstall