Czechs headed to the polls on Saturday for the final day of first-round voting in a presidential election that has put current pro-Russian President Milos Zeman up against liberal pro-European challengers.

Opinion polls showed 73-year-old ex-communist Zeman was leading the race ahead of eight other candidates, including his biggest challenger Jiri Drahos, a pro-European independent candidate who was formerly the head of the Czech Academy of Sciences.

Read more: Czech Republic starts voting for president

It is unlikely that Zemen will win an outright majority in the first round of voting, and a run-off vote is expected on January 26-27.

The first day of voting on Friday saw Zeman confronted by a topless anti-Kremlin protestor, who called him "Putin's slut" as he made his vote in Prague.

Read more: Czech presidential race boils down to Milos Zeman or not

Experts said the incident could increase his chances of being re-elected, judging by an outpouring of sympathy for him on social media.

The topless protestor from Ukraine's Femen group was overpowered by bodyguards and then arrested by police.

Security personnel also had to help a visibly rattled 73-year-old Zeman, who walks with a cane, to leave the room.

Read more: Visegrad represents Czechs, Slovaks, Hungarians and Poles

Zeman's campaign has centered on anti-immigration and a referendum on the Czech Republic's withdrawal from the European Union, even though he supports the country's membership in the EU.

His political views are similar to those of other populist-minded eastern EU leaders — including Hungary and Poland — that do not agree with Brussels over mandatory refugee quotas and other rules they see as efforts to limit national sovereignty.

He has used harsh words to describe the 2015 migrant crisis, saying it was "an organized invasion" of Europe and that Muslims were "impossible to integrate."

'President should work to unite society'

Drahos, who is seen as the biggest threat to Zeman in the election, is a liberal centrist who wants Prague to "play a more active role in the EU."

After submitting his vote in Prague Friday, Drahos said that the future president "should work in the interest of the pro-Western orientation of the Czech Republic."

Read more: Opinion: Czech voters more than simply right-wingers

"The president should work to unite society. It's clear that not everyone can agree, but the current president doesn't unite people, he divides them," Drahos added.

Other candidates in the running include ex-gambler and songwriter Michal Horacek, former right-wing premier Mirek Topolanek and Vratislav Kulhanek, former head of Czech carmaker Skoda Auto.

While presidents in the Czech Republic have little authority and limited political influence beyond the ability to make constitutional appointments, they can have a significant effect on public opinion.

Polls will close at 2 p.m. (1300 UTC) with preliminary results expected later on Saturday.

law/jlw (AFP, dpa, Reuters)