Both Vetevendosje (Self-Determination) and the Democratic League of Kosovo (LDK) snatched between 25% and 26% of the vote at the Sunday's parliamentary election, according to an early count.
Kosovo electoral commission bases the results on some 43% of the cast ballots.
They two opposition parties are followed by the PDK (Democratic Party of Kosovo) which is part of the ruling coalition and associated with President Hashim Thaci. The PDK won over 21% of the votes.
Initially, the PDK party claimed to be in the lead according to its own results, but later admitted defeat.
"We work hard to win this election, but we failed," said PDK leader Kadri Veseli.
"The people have spoken," he added.
The alliance coalition led by former Prime Minister Ramush Haradinaj (AAK-PSD) placed fort with 11.6% of support.
Read more: NATO countries urge Serbia and Kosovo to ease tensions
Guerilla leaders on their way out
Only the top-ranking party can be entrusted with forming the government, according to a decision by the country's Constitutional Court. Therefore, breaking the tie between the center-left Vetevendosje and center-right LDK is crucial for the future cabinet.
If LDK is ultimately declared the winner, its leader, 37-year-old university law professor Vjosa Osmani, might end up as the country first ever female prime minister.
Regardless of the outcome, however, the Sunday polls would be the first to oust the former guerilla commanders who dominated the scene for two decades. Both President Thaci and the outgoing Prime Minister Haradinaj fought against Serbian forces in Kosovo's 1999 independence war.
Serb List to claim all reserved seats
Voters went to the polls on Sunday amid calls for the Balkan country's politicians to resume dialogue with Serbia aimed at normalizing ties.
Haradinaj's government re-inflamed tensions with Belgrade by introducing 100% tariffs on imports from Serbia last year. The move comes as apparent retaliation to Serbia's diplomatic campaign to keep Kosovo out of key international institutions. The Kosovo prime minister stuck with the move despite pressure from Kosovo's main ally, the US, and criticism from the EU.
With the exception of Haradinaj, however, other key parties signaled they were ready to consider dropping the increase.
The snap vote came after Haradinaj resigned in July following a request from a Hague-based international tribunal to question him over crimes against ethnic Serbs during and after the war.
Read more: Kosovo lawmakers dissolve parliament, open way to election
One hundred of the 120 seats in parliament were up for grabs with about 1.9 million people eligible to vote. The remaining 20 parliamentary seats are reserved for ethnic communities, including the restive Kosovo Serbs, who have half of those seats. Virtually all of the Serb seats are expected to be claimed by the Belgrade-backed Serb List party.
Experts said the election is unlikely to produce a stable government, as no single political party is likely to win the vote on its own. It could take days, if not weeks, to forge a coalition.
dj,shs/sms (Reuters, dpa)
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