Recent polls suggest Harmony will remain the biggest party, followed by the ruling Union of Greens and Farmers and the populist KPV LV.
For Development/For, a new political alliance formed by several parliament members who left the center-right Unity party past year, received 12 percent of all votes, leaving the National Alliance in fifth place with 11 percent, down from 16.61 percent in the previous general election. In Riga, 30.6% of those who visited the polling stations voted for the party.
Saturday's election in Latvia, which sees 16 parties vying for 100 parliamentary seats, is being monitored by a team from the Organization for Security and Cooperation in Europe (OSCE).
The pro-EU, pro-NATO liberal For Development/For! party came fourth in the vote with 12.04 percent, beating parties from the current center-right governing coalition including the rightwing National Alliance, which earned 11.03 percent.
Members of the minority account for about 25 percent of Latvia's 2 million people, a legacy of almost 50 years of Soviet occupation that ended in 1991.
But Harmony's pro-Russian stance is still an issue.
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The Greens and Farmers' Union, the ruling centrist party of Prime Minister Maris Kucinskis, earned just 10 percent in this year's election in contrast to 19.53 percent in the 2014 election. Some 1.5 million Latvians were eligible to vote.
Russian President Vladimir Putin has taken a strong interest in defending the rights of ethnic Russians in the Baltics, and Latvia has felt Moscow's attempts to influence the country's affairs in media, business and politics.
Relations between Russian Federation and Latvia have been frayed by Russia's 2014 annexation of the Crimea Peninsula from Ukraine and its support for separatists in eastern Ukraine.
The Baltic nation has viewed Russian Federation as a security threat. But police said earlier they have found no systematic attempts by foreign nations to influence Saturday's election. Sunday's results give the party 23 seats, one less than in the last election.
Mr Kaimins has said he is open to working with Harmony if it condemns Russia's role in the conflict in eastern Ukraine and drops demands for Russian-language education in Latvian schools. "But I have lived in Riga my whole life and so have five generations of my ancestors", she told the AP.