Estonians began voting to elect a new parliament on Sunday in a poll that could bolster far-right nationalists, who have campaigned on opposing further arms deliveries to Ukraine.
Prime Minister Kaja Kallas's centre-right Reform Party is set to win, according to opinion polls, but will likely have to form a coalition to stay in power.
The party is expected to garner 28.7 percent of votes, according to a February survey by Kantar Emor that put the far-right EKRE in second place with 18.2.
The February poll placed the Centre Party on 13.4 percent, Estonia 200 on 13.4 percent, the Social Democrats on 10.1 and Isamaa (Fatherland) on 8.5.
Estonia, a country of 1.3 million people bordering Russia, has a unicameral parliament with 101 seats, all at stake in Sunday's vote.
The Baltic state, a member of the EU and NATO, has led international calls over the past year for more military aid to help Ukraine fight off Russia's invasion.
Estonia's military assistance to Ukraine currently amounts to more than one percent of GDP -- the biggest contribution of any country relative to the size of its economy.
"We support an open, friendly, Western-minded, European, smart country," Kallas told AFP in an interview.
"My biggest competitor thinks that we shouldn't help Ukraine, we shouldn't support Ukraine, we should only look for our self-interest," she said.
According to EKRE's leader, Martin Helme, Estonia should not be "further escalating tensions" with Moscow.
EKRE has campaigned against additional military aid to Kyiv, and called for an end to accepting Ukrainian refugees and for lower immigration rates to protect Estonian workers.
At the same time, the cost of living crisis has spiralled in Estonia, with one of the EU's highest inflation rates -- 18.6 percent in January over 12 months earlier.
- Abstention uncertainty -
The Centre Party, which is traditionally popular with Estonia's large Russian-speaking minority, has supported government policy on Ukraine and on Russia.
This has put off some Russian-speaking voters, and rates of abstention among the minority, around a quarter of the population, could be high.
Reform is a centre-right liberal party that appeals to business owners and young professionals.
It has promised to raise military spending to at least three percent of GDP, ease taxes on business and wants to pass a law approving same-sex civil partnerships.
The Centre Party is centre-left, and is promising more investment in infrastructure and affordable housing.
According to political analysts, a coalition between Reform, Estonia 200 and the Social Democrats is possible, as is one between Reform, Centre and Isamaa.
However, EKRE's chances of entering the government are projected as modest.
The polls opened at 9:00 am local time (0700 GMT) and will close at 8:00 pm (1800 GMT), with the first results expected early on Monday.
More than 47 percent of voters have already cast their ballot by post or online, according to the electoral commission.
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