Greek voters return Tsipras to power with strong win
* New Democracy leader concedes defeat
* Tsipras wins nearly as many seats as in first victory
* Tsipras to form government within three days -party source
* Syriza to restore coalition with Independent Greeks -source
Greek voters returned Alexis Tsipras to power with a strong election victory on Sunday, ensuring the charismatic leftist remains Greece's dominant political figure despite caving in to European demands for a bailout he once opposed.
With about a quarter of votes counted, Tsipras's Syriza party was on course to claim 35.3 percent of the vote, easily seeing off his main conservative challengers New Democracy on 28.1 percent.
The interior ministry said that would give him 144 seats in the 300-seat parliament, just five fewer than when he first stormed to power early this year. New Democracy swiftly conceded defeat.
A Syriza source said the party would turn once again to the small right-wing Independent Greeks party to form a coalition, restoring the alliance that first brought Tsipras to power nine months ago.
He called the election last month when his party split over his reversal on the 86 billion euro bailout, which he had accepted despite having won a referendum mandate to reject similar terms.
Tsipras expects to form a government within three days, another party source said.
"The electoral result appears to be concluding with Syriza and Mr Tspiras in the lead. I congratulate him and urge him to create the government which is needed," New Democracy's leader Vangelis Meimarakiis said.
Third place in the election looked set to go again to Golden Dawn, a far right party with a swastika-like symbol, with around 7 percent of the vote.
Tsipras's victory appears to have been stronger than some opinion polls had suggested. The firebrand leftist fought hard for Greece to be let off harsh austerity rules imposed by international creditors, only to back down last month after Greece's banks were shut and the country was pushed to the wall.
More than two dozen of his lawmakers abandoned him, many saying he had betrayed his principles. He argued that his tough negotiating stance softened the blow of austerity and persuaded creditors to agree a restructuring of Greek debt.
Apart from Golden Dawn and the communist KKE party, the major parties in the new parliament have now accepted the cash-for-reforms deal to keep Greece in the euro zone.
"After years of almost unprecedented crisis, the vast majority of Greeks are endorsing parties that are promising to keep the country in the euro even if that implies thorough and painful reforms," Holger Schmieding, chief economist at Germany's Berenberg bank said.
For former allies still opposed to EU-imposed austerity, however, Tsipras is a turncoat.
Yanis Varoufakis, the outspoken former finance minister who infuriated EU officials with his refusal to accept their proposals, called the election "the 'legalisation' of the capitulation that followed the signing of the dead end, humiliating and irrational" bailout.
The new government will also need to handle growing refugee inflows. Greece has been the main route into the European Union for tens of thousands of migrants arriving by sea, although nearly all of them quickly leave, heading north over land across the Balkans to richer countries like Germany.
In a painful reminder of that crisis, 13 migrants died in Turkish waters on Sunday when a boat carrying 46 people en route to Greece collided with a dry cargo vessel and capsized, a Turkish coast guard source said.