In a rousing speech in central Omonia Square on Thursday night, leftist SYRIZA leader Alexis Tsipras called on all Greeks, irrespective of their political affiliations, to back his party in Sunday’s elections as the only one that can guarantee the country’s exit from the crushing impact of a two-year debt crisis, using some of his harshest language yet against his conservative and Socialist rivals who signed the debt deal with foreign creditors.

“The die has been cast. On Sunday we turn the page,” Tsipras told a large, boisterous crowd. “On Sunday Greece will change. It will leave behind it fear and insecurity and those who tried to poison the Greek people with fear and insecurity, Mr Samaras and Mr Venizelos,” he said, referring to the leaders of New Democracy, Antonis Samaras, and PASOK, Evangelos Venizelos. “With their vote on Sunday for SYRIZA, the people will turn their backs on the two parties of bankruptcy, New Democracy and PASOK.”

Tsipras accused the two established parties of “looting Greece” and “lowering the Greek flag and giving it as a trophy to Angela Merkel,” the German chancellor. “Terrorize the terrorists on Sunday with your vote,” he said before reeling off a list of all the austerity measures that ND has promised Greece’s creditors it will implement, including sacking thousands of civil servants.

The 37-year-old leftist also sought to send messages beyond Greece’s borders. To market speculators, he said: “Don’t bet on Greece leaving the eurozone. You will lose.” He appeared to give a conflicting message to Europe, insisting that a Greek euro exit was not on the cards while suggesting that SYRIZA will drive a hard bargain in renegotiating Greece’s debt deal. “Merkel is scared because she will not be faced with people saying yes to everything,” he said.

Tsipras added that a 100-billion-euro bank bailout extended to Spain should pave the way for more lenient treatment for Greece. “If Spain can have financing without conditions, why can’t Greece stay in the eurozone without a disastrous memorandum?” he said.

On post-election collaborations, Tsipras was vague, saying he would seek collaboration with other parties even if SYRIZA has a majority. But he called on former PASOK ministers seeking a new portfolio to “vote for ND,” suggesting he will not cooperate with PASOK. He also vowed to change the electoral law to proportional representation, abolishing the 50-seat bonus granted to the first party.

In a related development, the leader of another anti-bailout party, Panos Kammenos, indicated that his right-wing group could cooperate with SYRIZA under certain circumstances.