Nairobi, Kenya ? Millions turned out Thursday for Kenya’s closest-ever presidential race – a contest pitting President Mwai Kibaki against a former ally – in relatively peaceful balloting after a campaign marked by violence and vote-rigging charges.

Lines at polling stations stretched for miles in some areas, a sign Kenyans are increasingly confident their votes count as the continent swings firmly toward democracy.

“This time around, Kenyans are not the same,” said Harun Owade, a 30-year-old mechanic who had been in line since 3:30 a.m. in the Kibera slum. “We cannot be tricked. We will put the politicians to the test.”

In the run-up to the vote between Kibaki and flamboyant opposition candidate Raila Odinga, clashes in western Kenya killed hundreds. An outlawed gang called Mungiki that had circulated leaflets in July calling on Kenyan youth to rise up against the government was blamed in a string of beheadings.

Wednesday, authorities said opposition supporters had stoned three police officers to death in western Kenya, accusing them of being part of a government conspiracy to rig the elections.

Thursday, supporters of a candidate in a rural area 300 miles west of Nairobi picked up a man suspected of bribing voters, and he fell from their truck and died. Local police chief Grace Kaindi said police were investigating whether the man was pushed from the moving vehicle, and were holding six suspects.

There has been bloodshed every election year since multiparty politics was re-introduced in 1992 after 22-year period as a one-party state. While 2007’s campaign has so far been less violent than past elections, several diplomats have expressed concern that a narrow victory on either side could lead to rioting by those who don’t accept or trust the results.

Kibaki won by a landslide victory in 2002, ending 39 years of rule by the Kenya African National Union and 24 years in power by Daniel arap Moi, who was constitutionally barred from extending his term. Moi’s blanket use of patronage resulted in crippling mismanagement and a culture of corruption that plunged Kenya into an economic crisis.

Kibaki, 76, has been credited with helping boost this East African nation’s economy, with a growth rate that is among the highest in Africa and a booming tourism industry. But his anti-graft campaign largely has been seen as a failure, and the country still struggles with tribalism and poverty.

Odinga, a 62-year-old former political prisoner under Moi, cast himself as an agent of change and a champion of the poor. But he has been accused of failing to do enough to help his constituents during 15 years as a lawmaker.

Kenya’s 14 million registered voters – out of a population of 34 million – also were electing 210 members of parliament and more than 2,000 local councilors. Most polls closed at 5 p.m., although several areas stayed open later because of delays in the morning.

The first official results were expected this afternoon.