Sunday’s poll will test the incumbent president for the first time since he came to power on a revolutionary wave.

Kiev, Ukraine – Voters in Ukraine will on Sunday cast their ballots to choose their sixth president, in the first test for incumbent Petro Poroshenko since he entered the top office in 2014 on the wave of the so-called Revolution of Dignity.

About 35 million people are eligible to vote, but several million of them in the Russian-annexed Crimea and the rebel-held parts of eastern Ukraine are unable or unwilling to cast their ballots.

Polls on Sunday will open at 8am (05:00 GMT) and close at 8pm (17:00 GMT). An early count is expected on Monday. If none of the candidates secures 50 percent of the vote, a runoff between the top two candidates will take place on April 21.

The race is contested by 39 contenders, but only three of them have a realistic chance of winning, according to opinion polls.

The latest surveys show comedian and political novice Volodymyr Zelensky leading with 20.6 percent, followed by opposition leader Yulia Tymoshenko with about 13 percent.

Poroshenko, who is projected to come third with 12.9 percent, said last week he would accept the result of the vote, “whoever wins”.

“I am ready to accept the victory of the Ukrainian people, because fair elections are a victory for the Ukrainian people,” he told Ukraina TV.

Ukraine presidential election: All you need to know

The vote will be monitored by observers from 18 countries as well as 139 Ukrainian civil society organisations, according to Ukraine’s Central Election Commission (CEC).

Some international watchdog organisations have voiced worries that among those accredited by the CEC were Ukrainian far-right groups.

In an interim report earlier this month, the OSCE Office for Democratic Institutions and Human Rights said that nearly all of its “interlocutors expressed concerns about the affiliation of many of these NGOs to particular candidates and doubted their intention to conduct election observation activities impartially.”

International watchdogs such as Human Rights Watch and Freedom House have also expressed worries about the inclusion of “the right-wing extremist forces” in the process.

Election campaign

According to the official financial reports provided by the candidates to the CEC, Poroshenko spent more than $15m during the election campaign; Tymoshenko about $6m; and Zelensky almost $4m.

Ukrainian law forbids the use of state funds for election campaigning, so candidates have to rely on donations or personal funds.

CHESNO, a watchdog monitoring politicians, political parties and their finances, told Al Jazeera that there were signs of violations in the funding practices of the top three candidates.

“Billboards of Poroshenko appeared during the campaign that were not paid for from his campaign funds. He said: ‘Oh, this is done by my supporters. I don’t know who they are.’ However, this is forbidden,” said Yuliia Reshitko, CHESNO’s communications manager.

“We want to know who was behind this. One billboard costs 150,000 hryvnia a week [$5,505] and they are all over Ukraine.”

For her part, Tymoshenko received funding by her party, Fatherland – however, the sources of her party members’ contributions are not clear, said Reshitko.

“There are a lot of people who donated 150,000 hryvnia [$5,505] to Tymoshenko’s campaign. And our investigation showed us that these people are pensioners, even homeless people. So, it is hard to understand where this money is from. Sometimes, they say that they have sold their passport data, or identification data to be used in the bank transfer,” she said.

Whereas Zelensky, who is mainly funded by different enterprises and individual donors, received money from Russia via an offshore account, according to CHESNO.

“He has a production company which is registered offshore where he received the money from Russia. Zelensky said he will abandon this offshore account and won’t receive money from Russia. But we will monitor that,” said Reshitko.

She said Ukrainian legislation is very strict on how the candidates can receive donations.

“A person who wants to donate money to any candidate’s campaign should physically go to a bank and pay any sum he or she would like to give. So, it is impossible to transfer money via online bank or something like that. In the bank, you have to show your passport, identification number, so everything is official.”

The pensioners want to support a military general, Anatoliy Hrytsenko [Oksana Parafeniuk/Al Jazeera]

Voters’ priorities

In a war-torn country struggling with corruption, concerns over the country’s territorial unity and financial wellbeing are expected to shape the outcome of Sunday’s vote – the two issues have been blamed for a deterioration in the standards of living, including an increase in the price of goods and a cut in subsidies amid rising inflation.

According to the United Nations, more than 13,000 people have been killed in the war that broke out in Ukraine’s Donetsk and Luhansk regions between Moscow-backed rebels and Kiev following Russia’s annexation of the Crimean Peninsula in March 2014.

Anatoliy Sokolov and Tetiana Sokolova, a pensioner married couple living 40km from the conflict zone on the outskirts of Severodonetsk town, said they would both vote for Anatoliy Hrytsenko, a former military officer who they believe will work hard to tackle both security issues and corruption.

“First of all, because he is a military man, he is a general. He will change the whole general staff in the army because it is like an almshouse right now,” said Sokolov, 65.

“Second of all, Hrytsenko is a determined person. He is the most honest,” he added.

“When Poroshenko came to power, we were full of hope. He did a lot of good, but if you put things that he did wrong, it will outweigh the good.”

Sokolov’s wife, 60, acknowledged the war made it difficult for Poroshenko to fulfil his promises, but still blamed him for the deteriorating living standards.

“Under Poroshenko, our standard of living lowered even more. I became a pensioner under his administration. I have a 30-year work experience as a kindergarten teacher and I receive 1,600 hryvnia [$58], they recently raised it by 100 hryvnia [$3.6],” she said, tearing up.

“I am very unsatisfied with the current government. They are all ‘thieves in law’.”

Myroniuk said she’d vote against all candidates if there’s such an option [Oksana Parafeniuk/Al Jazeera]

In the northeastern city of Kharkiv, Mariya Myroniuk, 19, told Al Jazeera that on Sunday she would probably back Zelensky “since he is not a fake candidate unlike about 20 of those who are listed on the ballot” just to dilute the votes in Poroshenko’s favour.

“I would vote for him just for that and also because he is a self-nominated candidate,” she said.

“He is not coming to power to enrich himself. He is coming for simply fulfilling his civic duties, by being a representative of the nation instead of a master of the people.”

However, Myroniuk, an international relations student at Karazin University, said she would not have taken part in the vote if she didn’t feel she had to fulfil her duties as a citizen.

“I would vote against all because I don’t like the election campaign and programmes of the candidates,” Myroniuk said.

“I don’t understand what’s the point of writing a 400-page programme and hang [a photo of] your face all over. It would be better to do something [for the country] and the actions would speak louder.”

Follow Al Jazeera’s Tamila Varshalomidze on Twitter @tamila87v