Polling stations opened in Ukraine at 8:00 am local time (5:00 am GMT) on Sunday in the country’s snap presidential election and operate until 8:00 pm local time (5:00 pm GMT).

Polling stations opened in Ukraine at 8:00 am local time (5:00 am GMT) on Sunday in the country's snap presidential election and operate until 8:00 pm local time (5:00 pm GMT). The new president will be elected for a five year term. Under a ruling by the Constitutional Court, the next presidential election will be due in March 2019.

Representatives of the Party of Regions (led by ousted President Viktor Yanukovych), oligarchs and maidan radicals are among the 21 presidential candidates.

Batkivshchyna party leader and former Prime Minister Yulia Tymoshenko and billionaire Pyotr Poroshenko are the favorites, according to opinion polls.

Poroshenko is widely expected to win the first round of voting. There is no minimum turnout threshold.

The election will be declared valid irrespective of how many actually cas their vote. Preliminary results will be announced on Monday, May 26.

The vote, scheduled by the Ukrainian parliament following February's overthrow of President Viktor Yanukovych, comes amid deep political crisis and large-scale military operations launched by the new Kiev authorities to crack down on protesters refusing to recognize the legitimacy of the current government.

The eastern Ukrainian regions of Donetsk and Luhansk earlier announced they would not take part in the election after the majority of their citizens voted earlier this month for self-determination as newly declared sovereign republics.

In mid-March, Ukraine's former republic of Crimea held a referendum which saw over 96 percent of voters in the region back the motion to secede from Ukraine and join Russia.

A total of 23 candidates were registered to take part in the upcoming vote, but several later announced their withdraw,  reducing the number to 21. According to expert estimates, there are two leading candidate in contention for the presidency; Yulia Tymoshenko,  a former prime minister and nominated by Ukraine's Batkivshchyna party and Chocolate king Petro Poroshenko of the UDAR party.

Recent polls suggest that 34% of respondents said they would back Poroshenko's candidacy, with 6.5% ready to vote for Tymoshenko.

According to a Ukrainian Constitutional Court ruling, the new president will serve a five-year term.

Moscow's position on the upcoming Ukrainian presidential election will depend on the conditions and manner of their conduct, Russian Foreign Minister Sergei Lavrov said last week.

Earlier Russia called for transparency during the vote and for respect for the interests of the regions.

Ukraine's presidential election is drawing wide international attention with leading world countries sending observers to monitor the electoral process.

The country's Central Election Committee has already registered a total of 2,784 observers and 1,183 reporters from 154 media outlets. More than 730 foreign observers have already crossed the Ukrainian border, about 100 have been sent by the US government with the same coming from the European Union.