Athens, May 23 : Greek Prime Minister Kyriakos Mitsotakis has decided to return the exploratory mandate he had received from President Katerina Sakellaropoulou to form a government following this weekend's inconclusive elections. During their meeting, he called for a second ballot to be held as early as June 25 if possible, according to an e-mailed press statement on Monday. In Sunday's general elections, the ruling conservative New Democracy (ND) party scored a landslide victory winning 40.79 per cent of the votes and thus 146 seats in parliament. The main opposition party, SYRIZA-Progressive Alliance, garnered 20.7 per cent of the votes with 71 seats. However, the ND failed to secure an outright majority in the 300-member parliament, Xinhua news agency reported. After the Speaker of parliament formally delivered the results to Sakellaropoulou, she launched the procedure foreseen by the country's Constitution, granting the first three-day mandate to the leader of the winning party. "I think that essentially the conditions for the formation of a government from the present parliament do not exist," Mitsotakis told Sakellaropoulou. Hours later, he called the President and told her that he wanted to return the mandate, according to a press statement. Sakellaropoulou will now grant three-day mandate to the leaders of the second and third-placed parties, the SYRIZA-Progressive Alliance and the socialist PASOK-KINAL, which received 11.46 per cent of the votes with 41 seats. She will receive SYRIZA-Progressive Alliance leader Alexis Tsipras on Tuesday, according to a press statement. If the overall process proves unsuccessful, a caretaker government will lead Greece to new elections. In the runoff elections, a revised electoral system will be used. This provides a bonus of up to 50 extra seats for the winning party, facilitating the formation of a single-party government. The frontrunner could gain an absolute majority in parliament with about 38 per cent of the votes under this system, according to political analysts. /IANS