KIEV, June 2 – Growing concern over possible fraud at several special mayoral and local elections in Ukraine on Sunday will probably keep tensions high among political parties during the next several weeks.

Mayoral elections in Yalta, Crimea, may have been marred in serious fraud during the last four hours of the vote, the Committee of Ukrainian Voters, an election watchdog, said Sunday.

The committee cited statistics that had registered a dramatic increase in turnout in the last hours of the vote without any visible increase in the number of people casting ballots.

At some polling stations, the number of people casting ballots during the last hour exceeded by 10 times the number of people casting ballots earlier in the day.

“These all have signs of a one systemic falsification, such as stuffing [unaccounted] ballots in boxes,” the Crimean branch of the Committee of Ukrainian Voters said in a statement after the vote.

“Committee observers later noticed thick packs of papers in ballot boxes at two polling stations, in Yalta and in Gaspra,” the committee said. “Right after that, local election commissions voted to remove the observers from the polling stations.”

A special mayoral election in Vasylkiv, in Kiev region, prompted similar concerns after top opposition Udar party leaders had arrived to the city Sunday night to defend the vote.

“Our representatives will stay in election commissions to make sure that the vote [counting] proceeds honestly,” Vitaliy Klichko, the leader of Udar, said at a press conference.

Asked if the party has a plan should the election appear to be rigged, Klichko said the party was prepared for such scenario.

“We have the plan of actions,” Klichko said. “If the there are falsifications, we will do everything to make sure that people’s will has been taken into account.”

The elections were an important for opposition groups ahead of the next presidential election that is due in March 2015. The mayoral vote in Vasylkiv was especially important for Klichko, who supported a leading opposition candidate.

Kolichko himself, along with Arseniy Yatseniuk, the leader of the opposition Batkivshchyna party, is seen as a major potential candidate to challenge incumbent President Viktor Yanukovych at the next presidential election.

Klichko’s candidate, Serhiy Sabov, was nominated as a single candidate from all opposition parties to try to defeat a pro-government candidate.

The elections in Yalta and Vasylkiv come after the Constitutional Court had ruled last week to postpone by at two years mayoral election in Kiev, the stronghold of opposition parties.

The court ruled that the next mayoral election and election of Kiev council should be conducted in October 2015, or after the presidential election in March 2015.

Serhiy Vynokurov, a deputy chairman of the Constitutional Court, in a prepared statement said that the ruling was aimed at making the frequency of elections “reasonable.”

Opposition groups accused Yanukovych of deliberately delaying the vote to make sure that Kiev infrastructure is controlled in March 2015 by a Yanukovych appointee to minimize the risk of a successful uprising should the election be contested.

Opposition groups will press for the Kiev mayoral election this year, but the attempt is likely to be defeated by the ruling Regions Party and may trigger another political crisis in Ukraine. (tl/ez)