The question of whether Prime Minister Pedro Passos Coelho will stay on, and on what basis, is the subject of intense negotiations.
Greek voters handed a stunning victory to the left-wing Syriza party and its leader Alexis Tsipras, as they went to the polls for the third time in a year.
Sanders denounced what he called the "political cowardice" of Republicans who "scheme to make it harder for people who disagree with them to vote."
The backdrop for elections in Greece, Portugal, Spain and Ireland is one of deep economic crisis ignited by the American financial collapse of 2007-08.
Otto Perez Molina resigned and was arrested on charges of corruption and accepting bribes; the elections that followed sent a confused message.
Voters will elect a new president to succeed Otto Perez Molina of the Patriotic Party, who is not allowed a second term.
If Thomas Mulcair has his way, he will head Canada's first social democratic government. With an election just called on Aug. 3, polls indicate that this may happen.
The red hammer-and-sickle banners of the Portuguese Communist Party and the green flags of the Green Ecological Party filled the streets of Lisbon.
The election was for the presidency of the "Turkish Republic of Northern Cyprus," an entity held to be illegal by the U.N.
Those familiar with the process attribute delays to the complexity of the ballots and a new system of voting and weighing votes.