The leftist Syriza coalition, led by Alexis Tsipras, won the general elections in Greece on Sunday, garnering 36.5 percent of the vote, with 25 percent of the ballots counted, the Interior Ministry said in its first official vote tally.
Prime Minister Andonis Samaras's conservative New Democracy party won 27.7 percent of the vote, the ministry said.
The final exit polls showed Syriza winning between 36 percent and 38 percent of the vote.
Syriza could end up with an absolute majority of 151 seats, with the party obtaining between 148 and 154 seats in Parliament, exit polls showed.
Former Prime Minister Yorgos Papandreu's Democratic Socialist Movement won only 2.5 percent of the vote and will not have any seats in Parliament.
The neo-Nazi Golden Dawn party finished in third place, the latest vote tally showed.
The election's outcome is "a historic victory that gives hope to Greek citizens, who have voted against austerity," Syriza said.
"This is the first step toward progressive development in Europe," the leftist party said in a statement.
The "new government will implement the Thessaloniki program to end the humanitarian crisis and will start negotiations with the creditors," the party said.
The head of Syriza's economic policy group, Yannis Milios, said Sunday that the agreement between Samaras and the Eurogroup "is dead."
"I suppose that (acting Finance Minister) Gikas Jarduvelis will limit himself at the Eurogroup tomorrow to talks of a technical nature, since the program that Jarduvelis had agreed to as Samaras's representative is dead," Milios said.
The Eurogroup, which meets in Brussels on Monday, planned to discuss the situation in Greece, but officials said ahead of the meeting that the agenda would depend on the outcome of the general elections.
The Greek Parliament implemented several rounds of austerity measures at the insistence of Samaras's government and the Troika - the European Union, European Central Bank and International Monetary Fund.
The austerity measures included cuts to social programs and the elimination thousands of public sector jobs.