Slovaks voted on Saturday in the first round of a tight presidential election pitting the Russia-leaning ruling camp against a pro-Ukraine candidate amid deep divisions on the war between the neighbouring rivals.

Parliament speaker and former prime minister Peter Pellegrini and liberal ex-foreign minister Ivan Korcok, who is backed by the opposition, are the clear frontrunners among nine contenders.

Pellegrini is supported by populist Prime Minister Robert Fico, who has questioned Ukraine's sovereignty.

Korcok is staunchly pro-Ukraine like outgoing president Zuzana Caputova, a government critic who chose not to seek a second term.

After casting his ballot, Pellegrini said Slovakia would stay anchored in the European Union and NATO after the election, despite Fico's remarks.

"Even if we talk about a more sovereign foreign policy this does not mean that the course of Slovakia's foreign policy should change," he added.

"People know what I stand for. Now it is up to them to go and vote," Korcok said after casting his ballot.

Caputova told journalists she hoped her successor would "represent our country abroad well".

 'Most visible Slovak'

Though the office is largely ceremonial, Slovakia's president ratifies international treaties, appoints top judges and is commander-in-chief of the armed forces.

The head of the NATO and EU member of 5.4 million people can also veto laws passed by parliament.

The latest opinion polls have suggested a tight race. An Ipsos agency survey indicated that Pellegrini would garner 37 percent of the vote, while Korcok would bag 36 percent.

An April 6 runoff is likely as neither is expected to win over 50 percent in the first round. Polling closes at 2100 GMT on Saturday.

Having travelled to Bratislava from Birmingham in England to vote, Ondrej Putra said the president was the "most visible representative" of Slovakia.

Korcok's "reputation and contacts."

Bratislava pensioner Juraj Jankovich meanwhile said Pellegrini would "put things in order in Slovakia".

"He is straightforward and he has never let people down. He was a calm and wise prime minister and he will be a good president," Jankovich added.

 Divided over Ukraine

Analysts say a Fico-backed president could further cement the government's anti-Ukrainian foreign policy.

"Pellegrini... will most likely act as an ally for the government coalition led by Robert Fico," Bratislava-based analyst Pavol Babos told AFP.

"Ivan Korcok will very likely be a counterweight to the government coalition, he will use various tools to correct their undemocratic tendencies," he added.

The war in Ukraine since February 2022 has been an electoral campaign fixture that has split the country.

Pellegrini recently told AFP Slovak politics were split in two groups -- those who want the war to continue and those who prefer peace negotiations.

"I belong to the latter," he said.

His long-time ally Fico has over the years appointed Pellegrini to various positions, including parliamentary speaker and education minister.

The 48-year-old became head of government after Fico was toppled as premier in 2018.

 'Peace cannot mean capitulation' 

Korcok is a diplomat who has represented Slovakia in the United States, Germany and Switzerland. The 59-year-old has criticised Fico's calls to negotiate with Moscow.

"The Russian Federation has trampled on international law... I do not think Ukraine should give up part of its territory to achieve peace," he told AFP.

In the final presidential debate, the two clashed over Ukraine, with Pellegrini urging "an immediate ceasefire and the opening of peace negotiations".

"Peace cannot mean capitulation," Korcok replied, adding that peace could come "immediately" on condition that Russian troops withdraw.

Though running as an independent, Korcok is backed by opposition parties who believe a Pellegrini win would pave the way for presidential pardons of government allies found guilty of corruption.