New Hampshire Sen. Kelly Ayotte, in Ukraine to monitor the presidential election, says voter turnout is high throughout the country, but lack of security in the Donetsk and Lugansk regions has prevented many from casting ballots.

"There's one person to blame for that security situation, and that's [Russian President] Vladimir Putin, because he's had strategic control of what is happening there," Ayotte said on "Fox News Sunday." "It's paid mercenaries. It's also the violence, and the intimidation and the fear for the people that live in that region."

Pro-Russian separatists in the eastern areas nearest the Russian border have vowed to not allow the election to take place.

Pro-Russian President Viktor Yanukovych was ousted from office earlier this year and fled to Moscow. Petro Poroshenko, heavily favored in the current election, has promised a more hard-line stance against Russia.

Poroshenko has said he would not accept Russia's annexation of Crimea and that he wants to reach out to eastern Ukraine to establish better ties with the highly ethnic-Russian population there.

Putin says he will respect Sunday's vote, though he has placed Russian troops near the border between the two countries over the past weeks.

As for tensions in the eastern areas, Ayotte said it is Putin "who can dial this up or dial this down."

There are no election observers in those areas, she said, but the vote in Kiev and other western parts of Ukraine appears to be offering "pushback" against Russian interference.

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