* Ukraine was promised visa-free regime by the European Union
* Kiev jittery about waning support in stand-off with Russia
* Ukraine minister sees 'complete impotence' in EU
* EU ambassador hopes for visa regime within weeks
By Pavel Polityuk and Matthias Williams
KIEV, Dec 6 (Reuters) - Ukraine feels let down by the European Union for not keeping to a promise to give its citizens visa-free travel in the bloc, senior Ukrainian officials said.
The comments, made by two senior officials in interviews with Reuters, were unusually outspoken and cut through the public displays of bonhomie shown at a Ukraine-EU summit in Brussels in November.
They are also a reflection of Ukraine's nervousness about being abandoned by Western backers in its stand-off with Russia over its 2014 annexation of Crimea and Moscow's support for separatist rebels in the Donbass region.
These worries have been heightened by events seen as playing into the Kremlin's hands, including the election of Donald Trump and the prospect of Francois Fillon, who favours thawing ties with the Kremlin, taking the French presidency next year.
Ukraine was promised visa liberalisation if it met a number of conditions, including steps to tackle corruption. But visa liberalisation has not materialised yet as the EU wants to put an emergency suspension mechanism in place first.
The mechanism would make it easier to suspend any visa-waivers if the bloc sees a sharp rise in overstays, asylum requests or readmission refusals from a non-EU state that has had travel rules relaxed.
"While of course the Ukrainian president and his delegation tried to keep optimism publicly, I understand very well if they return to Kiev somewhat disappointed," Anders Fogh Rasmussen, an adviser to Ukraine's president, said.
"I would even use a stronger word. I think it's a kind of betrayal from the EU side, taking into account that Ukraine has carefully fulfilled all necessary criteria for visa liberalisation," the former NATO chief said.
European Council President Donald Tusk, who spoke Ukrainian and exchanged jokes with Ukrainian President Petro Poroshenko at a joint news conference at the Nov. 24 summit, said he hoped the visa-free regime would be in place by the end of the year.
But Ukrainian Deputy Foreign Minister Olena Zerkal said the Europeans had shown little desire to implement visa-free access.
"Only constant pressure and the constant raising of this issue may force them to move forward," she said in an interview at her office. "Maybe this is not diplomatic, this is probably not diplomatic: we see complete impotence in the European Union, and in the European institutions."
Giving an example of the prevailing attitudes, she recounted an incident when, weeks before the summit, the Ukrainians were told by the French and Germans not to expect a positive decision.
"When I asked if they believe that it is unfair, that we in many areas are discriminated against compared to others, the German ambassador in Brussels told me 'life is not fair and you should cope with this'," she said.
EU officials publicly say Ukraine and fellow aspirant Georgia have qualified for visa liberalisation, but behind the scenes Germany, France, Belgium and Italy appear to be stalling.
"The EU understands that, in the eyes of Ukraine, the visa-free regime is a question of the EU's reputation," said a European diplomat, who declined to be identified. "The EU will try to do our best to provide the visa-free regime to Ukraine based on the understanding of these risks," he said.
"Not everything in Brussels revolves around Ukraine."
Representatives of EU states will discuss the issue again in Brussels on Wednesday.
Hugues Mingarelli, the EU ambassador to Ukraine, said Ukraine would be granted a visa-free regime as soon as the emergency suspension mechanism was agreed.
"We all hope that this will happen in the next few weeks. I cannot say anything more precise," he told a local news agency in an interview published on Tuesday.
The EU and the United States propped up Ukraine with money and diplomatic support after the country plunged into turmoil in 2014 and a new, Western-backed leadership took charge.
But since then, Ukraine's international supporters have become increasingly irked by what they see as Kiev's patchy progress in tackling corruption and modernising the economy. Some EU member states want sanctions on Russia lifted.
Ukraine, in turn, has its own grievances. Kiev has bristled at signs of a European rapprochement with Russia.
It also resents being told to do more to uphold its side of the Minsk peace process, brokered between Germany, France, Russia and Ukraine, to end the separatist violence in eastern Ukraine, saying the onus is on Russia as the "aggressor" nation.
The Maidan street protests in 2013/2014 were sparked by Ukraine's Kremlin-backed leader reneging on a plan to sign a political and trade agreement with the EU. But the fate of that deal, which was later signed, is now uncertain after Dutch voters rejected it in a referendum in April.
"I think that there are many things that can be considered as a betrayal," Zerkal said, when asked if the visa issue constituted a betrayal.
"The decision on Opal was also a betrayal of Ukraine," she said, referring to the European Commission allowing Russia's Gazprom to use the Opal pipeline in Germany, opening the way to bypass Ukraine as a gas transit route. (Additional reporting by Margaryta Chornokondratenko in KIEV and Gabriela Baczynska in BRUSSELS, editing by Peter Millership)