The head of Greece's main opposition party is meeting the country's president to return his mandate to form a government after failing to find coalition partners following the prime minister's resignation and call for early elections.

Evangelos Meimarakis, head of the conservative New Democracy party, returned the mandate Monday after the three-day limit. It now passes to the third-largest party in Parliament, a new group formed by hardliners who split from the governing radical left Syriza party last week. Neither party was expected to be able to form a government, and early elections are most likely to be held on Sept. 20.

Prime Minister Alexis Tsipras resigned on Thursday, just seven months into his four-year mandate, following a rebellion in his party over Greece's new bailout.