Muslim women ink their fingers at a polling place in Daura, Nigeria, Saturday. (AP) ABUJA: Nigerians turned out in large numbers Saturday to vote for a president as Africa's most populous nation sought to make history by holding its cleanest polls for head of state in nearly two decades. Voting began in a generally calm atmosphere in most of the country, though two explosions hit the northeastern city of Maiduguri late Friday and early Saturday, with no casualties reported.The same city was hit by two blasts during parliamentary polls last week. Polling stations across the country opened on time, and even earlier in some areas where large numbers of enthusiastic voters turned up and spoke of wanting to participate in a historic occasion in a country weary with flawed ballots. President Goodluck Jonathan, the clear favorite in the election, arrived at his polling place in his home state of Bayelsa in the oil-producing Niger Delta region, but declined to comment, saying he would speak later. The first four hours were dedicated to voter “accreditation” - a verification exercise that will be matched up against the number of ballots cast, one of the safeguards in place in an attempt to stop rigging. “There is no more rigging,” said Eghosa Osaguona, a 46-year-old trader at an Abuja polling unit. “More and more people are aware of their rights.” Jonathan has staked his reputation on the conduct of the polls, repeatedly promising a free and fair election in the continent's largest oil producer long held back by corruption and with a history of vote fraud and violence. His main challenger is ex-military ruler Muhammadu Buhari, who benefits from significant support in the country's north and has developed a reputation as an anti-graft figure, though his regime in the 1980s was also accused of outrageous rights abuses. An enormous effort has been undertaken to hold a credible vote, but violence poses a risk, with bomb blasts and other attacks having killed dozens in the run-up to the polls, including during last week's parliamentary ballot. More than 73 million people registered to vote in the vast West African nation. There are two other main candidates in the race: Nuhu Ribadu, the former head of the country's anti-graft agency, and Ibrahim Shekarau, governor of the northern state of Kano. – Agence France