Nigerians went to the polls today to choose state governors and legislators in the first of two elections which should lead to a historic political transition in Africa's most populous nation.
The conduct and results of the vote at state level will provide an indication of what to expect from presidential polls in a week's time.
Fatal attacks yesterday and today and have been linked to the elections and early indications are that electoral officials and materials are absent from most polling units in the three largest cities two hours after voting was due to begin.
A spokesman for the Independent National Electoral Commission said officers in Lagos, an opposition stronghold, were delayed by a last-minute security alert that forced the authorities to deploy extra troops and police on the streets.
He had no explanation for the lack of voting in the northern metropolis of Kano or in the southern oil capital Port Harcourt.
The killing of dozens of people in political violence in recent months, the disqualification of many opposition candidates and poor preparation have raised doubts about the credibility of the vote.
And there were further attacks in the past 24 hours. In Port Harcourt, suspected militants torched two police stations early today, killing seven policemen and releasing suspects from the cells, security sources said.
Yesterday, three local politicians were gunned down in a house in nearby Yenagoa and a Muslim cleric was assassinated in a mosque in Kano.
Nigeria returned to democracy in 1999 after three decades of almost continuous army rule, and these elections should bring the first handover from one elected president to another since independence in 1960.
In eight years of democracy, more than 15,000 people have been killed in ethnic, religious and communal fighting - often stoked by politicians carving out territory for themselves.
Parties have traded accusations of plans to rig or disrupt the polls, and rights groups have accused President Olusegun Obasanjo of meddling in the process to favour the PDP.
Mr Obasanjo must step down after serving for the maximum eight years and he has promised free, fair and transparent polls.
The opposition Action Congress has said thousands of supporters and several candidates have been detained.
The ruling People's Democratic Party (PDP) now controls 28 of the 36 states, with the rest split between a handful of opposition parties.
With unrivalled funds and powers of incumbency, analysts say the PDP should coast to victory.
But endemic corruption, failure to deliver basic services and deteriorating security have boosted the chances of the opposition in many states.
"If Nigeria works well, so might Africa. If the democratic experiment in Nigeria stalls, the rest of Africa suffers and loses hope," said Robert Rotberg of the US Council on Foreign Relations in a special report.