Brussels - European Union fears that a new gas row between Russia and Ukraine could come as early as July reached the highest levels Thursday, as EU leaders planned to discuss them at a summit in Brussels.

"In July this will become a real problem: Ukraine will have no money to pay for gas for storage. (The summit) is the last opportunity to give guidance to the European Commission on what to do," a top politician from an EU member state said ahead of the summit.

In January, a dispute between Ukraine and Russia's gas monopoly, Gazprom, cut off gas supplies to a swathe of EU states in Central and Eastern Europe.

Last week, the Czech government, which currently holds the EU's rotating presidency, and the commission, the EU's executive, sent a team of experts to Russia and Ukraine amidst fears that Ukraine might be unable to pay Gazprom for gas which it would store during the summer and then sell on to EU customers in the winter.

Commission chief Jose Manuel Barroso will brief EU leaders on the report at Thursday's summit, commission energy spokesman Ferran Tarradellas said.

But ahead of the summit, top officials said that the experts had concluded that Ukraine would be unable to pay for EU-bound gas in July - with serious effects for the EU's consumers.

"Of course it's an issue again. It's not very clear what the reasons are, whether it's just that the Ukrainian government has no money or whether it is some kind of new strategy from (Russian) prime minister (Vladimir) Putin," Lithuanian Prime Minister Andrius Kubilius told the German Press Agency dpa.

However, the summit was unlikely to propose concrete solutions, Kubilius said.

"The EU has no such funds to step in. Perhaps European gas infrastructure companies will have to have some kind of arrangement, but that is up to the companies," he said.

Separately, experts on the gas industry from EU member states met officials from the Ukrainian and Russian gas monopolies on Thursday in Brussels to debate the same issue.

"Due to rising concerns on a possible disruption of Russian gas supplies to Europe through Ukraine, the commission decided to invite (the two sides) to explain what the situation is," Tarradellas said.

EU experts will assess the replies after the meeting, he said. (dpa)