Greece's caretaker prime minister Vassiliki Thanou (L) escorts outgoing Prime Minister Alexis Tsipras following a handover ceremony at the prime minister's office at Maximos Mansion in Athens, Greece August 27, 2015. [Photo/Agencies]

No cooperation

Tsipras' Syriza party is expected to once again emerge as the biggest party in Parliament when the snap election is held. But Tsipras is not expected to secure an absolute majority, forcing him to find a coalition partner, failing which a second round of elections could be held.

In an interview with Alpha TV on Wednesday, Tsipras stood by previous comments that his party would not cooperate with New Democracy and the socialist PASOK, which took turns ruling Greece for decades before Syriza swept to power this year.

He also ruled out a tie-up with the new, centrist and strongly pro-euro To Potami party, effectively making his current coalition partner, the right-wing Independent Greeks, his only potential ally.