Estonia's ruling center-right Reform Party won the most votes in general elections Sunday, beating a pro-Russian party in a close fight that centered on taxes and national security amid Kremlin's moves in Ukraine.

With nearly all ballots counted, Prime Minister Taavi Roivas" Reform Party had gained 27.7% of the votes, down from 28.6% in the last general elections in 2011, but still ahead of the pro-Russian opposition Center Party, which got 24.8% of votes, a record for the party and up from 23.3% four years ago.

Recent polls had the two parties neck to neck in a race that saw many votes split along ethnic lines in this nation where one-quarter of 1.3 million people are ethnic Russians.

Many Estonians worry that the Center Party, which has a cooperation treaty with Russian President Vladimir Putin's United Russia, could be part of a Russian-led campaign to destabilize their country. For them, the Reform Party offered stability at a time when the East-West split that has accompanied the Ukraine crisis is fueling concerns that Moscow may attempt to reassert its power over other former Soviet states after annexing Crimea.

Mr. Roivas said in his victory speech that he will speak about the possibility of forming a new government with the current junior coalition party, the Social Democrats, and likely seek out one more partner to secure a majority in the 101-member parliament.

He ruled out a coalition with the Center Party, whose leader, Tallinn Mayor Edgar Savisaar, has riled his political opponents who criticize him for not condemning Russia's actions in Ukraine and accuse him of using municipal money for election campaigns.

"We're the only party who did not lose mandates," Mr. Savisaar said in a speech shortly after the results were announced. "The other three major parties have reason to think, especially considering they have all been in the government during the last four years."

The Social Democrats got 15.2% of the votes, down from 17.1%. A former coalition partner of the Reform Party, the conservative Pro Patria and Res Publica Union suffered the biggest drop in support with 13.7%, down from 20.5% in 2011.

Two populist newcomers--the anti-immigration Conservative People's Party of Estonia and the Estonian Free Party--both made it into parliament for the first time, with 8.1% and 8.7% of votes, respectively.

Estonia, like its Baltic neighbors, regained independence from the Soviet Union in 1991 and has since joined both the European Union and the NATO alliance.

In election campaigns, Mr. Roivas touted the need for increased national security amid widespread concerns that the Baltic countries, including Latvia and Lithuania, could become a Kremlin target. Last year, the alleged kidnapping of an Estonian security agent by Russian officers heightened tensions between the countries, which share a 200-mile border. Repeated air incursions by Russian fighter jets over Baltic airspace have also fueled anxieties.

"He [Mr. Savisaar of Center Party] has his eyes to the east. This scares me," said 84-year-old Heda Eller, who was born in Estonia before the Soviet occupation during World War II, after casting her vote for the ruling Reform Party.

Other issues dominating the election run-up were taxes and wages, including proposals to introduce a progressive income tax and raise the minimum wage. Many Estonians are still feeling the legacy of low wages from the Soviet days as well as cutbacks suffered during the recession that followed the 2008 financial crisis. Many workers, especially outside the capital, are living on the edge of poverty, and want to see higher income.

A total of 64.2% of eligible voters went to the polls, including 20% of Estonians who voted online.

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