Athens, Greece (CNN) -- The leader of the socialist PASOK party in Greece is starting efforts to build a government, his party said, making him the third Greek politician since Sunday to try to do so. PASOK leader Evangelos Venizelos held meetings with the leader of the Democratic Left party, Fotis Kouvelis, in what Venizelos called a "first step" toward assembling a coalition of pro-European parties. He is scheduled to hold talks with head of the center-right New Democracy party, Antonis Samaras, on Friday. Samaras and another potential coalition partner -- Alexis Tsipras of the leftist Syriza party -- have tried and failed to organize a government already. If no one can pull together a coalition, and no national unity government can be formed by May 17, Greece must call new elections.
@highlight
NEW: Socialist leader Venizelos calls talks a "first step" toward a coalition
@highlight
Opinion poll suggests the leftist Syriza party would win most votes in a new election
@highlight
Two other politicians say they can't get enough backing from other parties to form a coalition
@highlight
If no government is formed by May 17, Greece has to call new elections
As @placeholder began coalition talks Tuesday, he said PASOK and New Democracy "don't have a majority any more to vote for the plundering of the Greek people."