French President Jacques Chirac said Thursday efforts to combat climate change required mandatory European Union targets to boost renewable energy but also demanded increased reliance on nuclear power, according to dpa. "We should collectively fix an ambitious objective for low-carbon energy in Europe," said Chirac, according to French diplomats, as EU leaders met in Brussels to try and clinch a ground-breaking deal to fight global warming. The French President said he favoured the goal of increasing renewable energy use in Europe. But "this is only a partial response," cautioned Chirac. "We know that we will need to use other low-carbon energy sources - clean coal and nuclear - to achieve our objectives against climate change," he said. Chirac underlined that France, which is a major user of nuclear power, had lower carbon dioxide emission levels than Germany. The French leader's comments came as 27 EU leaders struggled to clinch a landmark climate change pact, including measures to increase use of renewable energy and cut CO2 emissions. The 27-nation bloc is badly split over German Chancellor Angela Merkel's call for governments to agree a mandatory target of 20 per cent for increasing the share of renewable energy use in overall EU energy consumption by 2020. Renewable energy currently accounts for 7 per cent of EU energy usage. Germany is current president of the EU. Backing the French line on nuclear power, Czech Prime Minister Mirek Topolanek said that "nuclear energy has been one of the most important carbon-free energy sources contributing to reducing emissions of greenhouse gases." "As the price of nuclear energy does not depend on oil prices and no uranium shortages are foreseen...nuclear energy significantly contributes to the security of supply in the EU," he said. Britain, Luxembourg, Sweden and Denmark are among key nations, backing the German call for tougher goals on renewable energy use. "If we don't manage to set targets for renewables, then Europe will not assume a leadership role," warned Luxembourg Prime Minister Jean Claude Juncker. "I think the European Union should go green," said Danish Premier Anders Fogh Rasmussen, adding: "I'm in favour of binding targets...we should focus much stronger on renewable energy." However, the renewable energy plan has run into opposition from several EU states. EU businesses also oppose setting legally binding targets on renewables, arguing this would put Europe at a disadvantage compared to its competitors. In addition to France, Finland and a number of EU newcomers, including the Czech Republic, Hungary and Bulgaria, also oppose a sole focus on renewables. Finland is a high consumer of energy for its paper industry and coal remains a vital source of power in central and eastern European states. Governments in the region also say they do not have the resources required to invest in expensive renewable energy. France's focus on nuclear, however, ran into strong resistance from Austria. "We would not accept any European wording that puts an emphasis on further concentration on nuclear energy," said Austrian Chancellor Alfred Gusenbauer. The Austrian leader said the summit must not send a signal that "the future green energy is nuclear energy." Given the rift, Merkel warned of a "tough debate" at the summit on action to increase green fuel use across the bloc. She said Germany was braced for hard bargaining at the meeting. "We still have to do a lot of work...we have tough debates, tough negotiations ahead of us," Merkel said, adding that the EU's global credibility as a leader on environmental issues was at stake. "I am confident that after such a long debate we will be able to show that Europe is in the vanguard on climate change," said Merkel. On further action against global warming, leaders were likely to agree on a unilateral EU cut in emissions of greenhouse gases by 20 per cent in 2020 compared to 1990 levels - but difficult negotiations are expected on the share-out of such reductions. Under the EU plan, the bloc could opt for an even steeper 30-per- cent cut if there is a new international climate change deal, including the US and other major global polluters. The EU accounts for about 14 per cent of global greenhouse gas emissions while the United States, the largest polluter, produces some 25 per cent. The commission has said that investment in a low-carbon economy will require around 0.5 per cent of total global Gross Domestic Product (GDP) over the period 2013-2030.