The European Union's top leaders are set to discuss the troubled gas trade between Russia and Ukraine at a summit on June 18-19 following a warning from Vladimir Putin, dpa cited the head of the EU's executive as saying today. The Russian prime minister called European Commission chief Jose Manuel Barroso on Friday to warn him of "difficulties he anticipates in payments coming from Ukraine" to Russian natural-gas monopoly Gazprom, Barroso told journalists in Brussels. Putin explained that "Ukraine has asked for some support with the financing of these payments," Barroso said. Barroso said that he would raise the issue with the heads of state and government of the EU's 27 member states when they meet for a summit in Brussels on June 18-19, "to see what it is possible to do." Ukraine's economy is reeling under the impact of the global economic crisis, needing a massive bail-out from the International Monetary Fund to stabilize its currency. Barroso said that it would be "difficult, if not impossible," for the EU to provide any assistance from its central budget, either to add to the IMF package or to make it easier for Kiev to pay its Gazprom bills. The EU is currently under massive pressure to bail out governments, companies and industry sectors in Europe which have been hard hit by the economic crisis. A quarter of all the natural gas burned in the EU comes from Russia, and 80 per cent of that amount passes through pipelines in Ukraine, making the relationship between Ukraine and Gazprom vital for EU security. Twice in the last three years, rows over allegedly unpaid bills between the EU's two neighbours have provoked Gazprom to cut off all gas supplies to Ukraine. The most recent row, in January, cut off gas supplies to a number of EU member states for almost a fortnight in the midst of a bitter cold snap. "It is important to work to avoid a new crisis like the one we had in the beginning of this year," Barroso said. However, he also stressed that the issue is "mainly a problem between Russia and Ukraine."