The vote count has begun a day after Ukrainian elections for mayors and council representatives that are seen as a survival test for President Petro Poroshenko’s fragile ruling coalition.
Final results are not expected to be announced before October 28, and runoff ballots are expected to be necessary in mid November to determine the mayors of several cities.
Ukrainians cast ballots across the country October 25 except in eastern areas controlled by Russian-backed separatists and the Crimea peninsula, which was annexed by Russia last year.
Polling stations also remained closed in Mariupol, a port city near rebel-held areas on the Sea of Azov, following a dispute over the ballots, which were printed at a company controlled by influential tycoon Rinat Akhmetov, prompting fears of fraud.
"The election must be delayed because some of the ballots had serious problems," said Natalya Kachtchi, a member of the local election commission.
The polls in Mariupol "were aborted...due to the improper preparation of election ballots, the absence of control over their printing and number, and reliable storage,” Poroshenko's Solidarity party said in a statement.
Solidarity is projected to take the biggest number of mayoral seats and local legislatures. But the president's approval rating has slipped to 26 percent, amid continuing economic turmoil and the insurgency in the east, where violence has ebbed in recent weeks.
Prime Minister Arseniy Yatsenyuk, whose approval ratings reportedly have plunged to just a few percentage points above zero, is not even fielding candidates from his party.
Live Blog: The Elections As They Happened
One beneficiary of weaker support for Porshenko's allies could be the Opposition Party, largely made up of former members of the Party of Regions, which was Viktor Yanukovych’s party until violent clashes in Kyiv resulted in his ouster in February 2014.
In many parts of eastern Ukraine -- a stronghold for the former Party of Regions -- pro-Russian politicians have remained in local power positions despite 2014 demonstrations known as Euromaidan.
The Opposition Party, which currently holds about 10 percent of the seats in the national parliament, rejects Poroshenko's goal of bringing Ukraine into NATO and favors nonalignment.
It advocates ending the war in the east peacefully by negotiating with Russia and seeks a return to Ukraine's 1991 borders, reestablishing Crimea and parts of eastern Ukraine currently under rebel control as Ukrainian territory.
Another beneficiary of the vote could be the Batkivshchyna Party of Yulia Tymoshenko, a top opposition leader and former prime minister who is now demanding a “professional army and fair tariffs” in Ukraine.
Tymoshenko and her allies are expected to do better than their disappointing sixth place finish in parliamentary elections last October.
Political analysts also are closely watching Andriy Sadovyy's Self-Help faction, which rose from relative obscurity to finish in third place in the parliamentary elections.
Sadovyy himself is fighting for a third term as mayor of Lviv amid critics' charges that he has become too distracted by national politics to lead the capital city.
In Odesa, the Black Sea port that is Ukraine largest, reformists are battling to oust incumbent Mayor Hennady Trukhanov in what is seen as a direct challenge to the country’s oligarchic elite.
Challenger Sasha Borovik, an aide to regional Governor Mikheil Saakashvili, is running with the support of Poroshenko's bloc.
Separatists in control of portions of the Luhansk and Donetsk regions have blocked holding the elections there.
The separatists originally threatened to hold their own local elections on October 18 but later postponed the date to February next year -- reportedly under pressure from Moscow.
In addition to those living in the separatist-controlled areas, some 1.5 million people who have fled from eastern Ukraine and Crimea and now live scattered across the country reportedly had difficulties in voting.
The local elections were intended to set the stage for a planned devolution of more power from Kyiv to municipal bodies in the future.
The new powers could include keeping more locally collected tax money at home instead of sending it to Kyiv to be reapportioned by the central government. However, change could come slowly because devolution includes demands for greater autonomy in the east.
Demands put forth by pro-Russian separatists are part of the Minsk peace process and are the subject of hot debate in the Ukrainian legislature as it discusses amendments to the constitution that would be necessary for any new decentralization of power.
The local elections are not supposed to impact the implementation of the Minsk accords, which created a roadmap for a ceasefire and political settlement to the conflict in eastern Ukraine. That’s because implementation of the Minsk accords is the responsibility of the central government.
But analysts say a strong showing by the Opposition Bloc and the Batkivshchyna Party could weaken Poroshenko’s political clout and ability to win over votes in parliament needed to implement the Minsk agreements.
With reporting by RFE/RL's Charles Recknagel in Prague, Reuters, AP, AFP, dpa, Kyiv Post, TASS, and Interfax