KIEV, October 23 (RIA Novosti) - Ukraine's opposition Party of Regions on Friday officially nominated as presidential candidate its leader Viktor Yanukovych, seen as a frontrunner in the upcoming elections.

Ukrainian pollsters say none of the candidates is likely to garner 50% plus one vote, required to avoid a runoff, in the January 17 polls.

Recent surveys give Yanukovych, a former prime minister widely seen as pro-Russian, a 10-12% lead over Prime Minister Yulia Tymoshenko. She has about 15% and former parliamentary speaker Arseniy Yatsenyuk is placed third with some 9%. However, up to 25% of voters are uncertain about their vote in the second round, making the final result less predictable.

Tymoshenko is to formally announce her participation in the elections on Saturday, during a rally on Kiev's Independence Square, the main venue of street protests against alleged ballot rigging, which swept President Viktor Yushchenko to power five years ago.

Yushchenko, who defeated Yanukovych in an election re-run, now trails with under 10%.

The registration deadline is November 9.