Voting is underway in two states in northern Nigeria where polling was delayed by violence that followed last week's presidential election. Nigeria's ruling party retained the presidency, but appears to have lost control of several state governments.
Security forces accompanied electoral workers to polling stations in Kaduna and Bauchi where state-wide elections were postponed after supporters of opposition presidential candidate Muhammadu Buhari last week battled riot police following the election of President Goodluck Jonathan.
The human rights group the Civil Rights Congress of Nigeria says at least 500 people were killed in violence across the north. Vice President Namadi Sambo's home in Kaduna was set on fire.
Observers say early voter turnout in Kaduna and Bauchi Thursday was smaller than during the presidential poll. Some Buhari supporters destroyed their voter cards after their candidate said the presidential ballot was rigged.
But Buhari says that is a mistake and is calling on his supporters to come out for the poll, which he says is an opportunity to "disgrace your oppressors who have stolen your votes"?.
President Jonathan's ruling People's Democratic Party currently controls the governorships of Kaduna and Bauchi but is facing strong opposition candidates from Buhari's Congress for Progressive Change party.
Buhari's party is challenging results from Tuesday's gubernatorial elections in Niger and Katsina states. The opposition Action Congress of Nigeria party is contesting the outcome of the gubernatorial election in Akwa Ibom.
That party held on to control of the commercial capital, Lagos, and appears to have defeated the ruling party in the states of Ogun and Oyo, putting opposition parties in control of all six states in the southwest region.
The ruling party also lost control of Zamfara and Nasarawa states, but retained control in the oil-rich Niger Delta and picked-up the governorship of Kano, which is the north's most populous state.