KIEV, Oct. 25 - President Petro Poroshenko's fragile ruling coalition faced a major survival test Sunday in local elections marred swiftly by polls failing to open in the strategic port of Mariupol, AFP reported.

A smooth vote and show of support for Poroshenko's contested austerity measures and faltering anti-corruption drive could help his loosely-knit alliance gain momentum and keep the former Soviet republic on track for eventual EU membership.

The vote comes during a lull in fighting with pro-Russian eastern separatists that has Kiev worried about Ukraine slipping off the global radar despite the perceived threat posed by Moscow and dire economic effects of the war.

But politicians were even more urgently concerned about what happens in Mariupol -- a vital outlet for the east's industrial output that provides a potential land bridge between separatist regions and Ukraine's Russian-annexed Crimea peninsula.

The southeastern city of 500,000 came under repeated attacks and one major takeover effort by the militias in the bloodiest days of the 18-month war.

And the partially-emptied city is still overseen by rival factions allegiant to various regional field commanders and oligarchs.

Poroshenko's Solidarity party said the Mariupol vote was pushed back "due to the improper preparation of election ballots, the absence of control over their printing and number, and reliable storage."

Washington's Ukraine Ambassador Geoffrey Pyatt came out in strong support for what he called the Ukrainian leader's "commitment to ensuring that the people of Mariupol — like all citizens of Ukraine — are able to make their own democratic choice."

The popularity of Poroshenko's government has plunged as utility bills soar and other belt-tightening measures bite under the terms of an austerity pledge Kiev gave to world donors in return for $40 billion (36 billion euro) in help.

The party of Prime Minister Arseniy Yatseniuk -- a top Poroshenko partner who beat the president's party in October's parliamentary vote -- has seen its approval languishing near zero and fielded no candidates.

Frustration at the West's refusal to arm Ukrainian forces and only provide tightly-regulated financial help has further bolstered the election odds of the marginalized but militant far right.

Polls show that pro-Russian groups are also gaining momentum because of Kiev's effective economic blockade of rebel-run regions in which an estimated 3.5 million people still live.

Poroshenko's confident promise the day after his presidential triumph to stamp out the insurgency within a matter of days has also done little to help his cause.

The demoralized mood of voters has been picked up by an astounding 132 parties -- many of them using boastful slogans and colorful characters to draw in the media and prompt endless TV debates. (afp/ez)