Nigerians went to the polls on Saturday 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.
Early indications were that electoral officials and materials were absent from most polling units in Nigeria's three largest cities two hours after voting was due to begin.
The conduct and results of the vote at state level will provide an indication of what to expect from presidential polls in one week's time.
"I have been here for more than two hours but nobody has shown up. We are ready to wait because we are determined to vote," said Segun Olayemi, a computer technician in the densely populated Obalende district of Lagos, Nigeria's largest city.
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, where a Muslim cleric was assassinated in a mosque yesterday, or in the southern oil capital Port Harcourt.
Dozens of people have been killed in political violence in the months leading up to the poll, dozens of mostly opposition candidates have been disqualified and poor preparations have raised doubts about the credibility of the vote.
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.
"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.
In Port Harcourt, the largest city in the oil producing Niger Delta, suspected militants torched two police stations early today, killing seven policemen and releasing suspects from the cells, security sources said.
In nearby Yenagoa, three local politicians were gunned down in a house yesterday. Nigerian governors control big budgets and have enormous powers in their states, making the gubernatorial polls as important to many Nigerians as the April 21 presidential vote.
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.
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.
This election presents a unique opportunity for a new elite to assume power, wealth and influence in the regions.
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.
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.
Obasanjo advised Nigerians to limit travel during election days to curb violence and fraud. The government ordered Nigeria's land borders to be closed all day today.