Russia and Ukraine dashed expectations that they would end their long-running gas dispute on Tuesday, with Kiev’s inability to pay for its gas debts to Moscow emerging as the main obstacle. Ukraine agreed to pay $3.1 billion toward its debts by the end of the year. Kiev now needs to raise $1.6 billion in additional funding before the two sides meet again next Wednesday, when the European Union said it was hopeful an interim deal could be signed that could avert gas shortages this winter, Russian and EU energy officials said. The failure to resolve the deadlock comes despite heightened expectations over the past days both sides had agreed on all the main elements of a deal.