LAGOS/PORT HARCOURT, Nigeria, April 12 (Reuters) - Voting for Nigeria's powerful state governors was extended on Sunday in several states after ballot box snatching and violence in some districts, particularly in oil hub Rivers state, electoral commission officials said.
The 36 governors are among the most influential politicians in Nigeria, Africa's biggest oil producer and economy, with budgets larger than those of small nations.
Observers and voters said the turnout to elect 29 governors and state assemblies on Saturday was low compared with the presidential vote last month, which was considered the freest and fairest yet and has paved the way for the first democratic transfer of power in the country.
"The election in some units of 6 councils was inconclusive and a fresh election will be held today," Rivers resident electoral commissioner Gesila Khana told journalists.
In the presidential poll, Muhammadu Buhari of the All Progressives Congress (APC) beat President Goodluck Jonathan of the People's Democratic Party (PDP) with 15.4 million votes to 13.3 million.
A written statement from the Independent National Electoral Commission (INEC) in Rivers said the governorship election was "cancelled in all the places where electoral materials were snatched".
INEC headquarters in the capital Abuja said the election went "very well" across the country but there were 66 instances of violence at polling units, with highest number seen in southern and south-eastern states.
Rivers had the highest incident rate at 16, followed by Ondo, Cross River, Ebonyi and Akwa Ibom.
On Saturday, at least 10 people were killed in election-related violence across the country. On Sunday, a police spokesman in Ebonyi state said the PDP chairman of one government area was shot by thugs in his house.
More than a dozen people were killed during the presidential polls, mainly due to attacks by Islamist extremist group Boko Haram, which has been waging a six-year insurgency in the northeast of the country.
A large protest, shoot-outs in several towns and attacks on INEC property delayed the start of voting in Rivers.
Gubernatorial candidates threatened to protest should INEC announce any results and current governor Rotimi Amaechi called the polls a "sham" after attending a 2,000-strong APC protest in the state capital Port Harcourt on Saturday.
INEC said 5.2 percent of polling units across the country did not open until 1 p.m. (1200 GMT).
Polling in a few other states was also extended or was being debated, while collation and counting was still on-going in many others. Some results are expected to be announced on Sunday.
Borno state INEC spokesman Tommy Magbuin said polls re-opened in three local government areas in the northeastern state after ballots were not delivered to polling stations in time. INEC missed the name of one candidate and had to reprint them last week.
In the south-eastern state of Imo, ballot boxes were stolen in three districts, which could mean a vote extension while in Anambra, polls in one area will be pushed back due to irregularities and violence, INEC officials said.
In Bayelsa, where only state assembly elections were taking place, the vote was rescheduled in eight out of 24 constituencies due to insufficient electoral materials and other areas could be re-done as well due to skirmishes. (Additional reporting by Anamesere Igboeroteonwu in Onitsha, Buhari Bello in Jos and Lanre Ola in Maiduguri; editing by Philippa Fletcher)