LAGOS More than 500 people were killed in post-election violence last week in the mostly Muslim north, a Nigerian human rights group said on Sunday, and it warned of further unrest during state elections.
Youths launched protests in northern towns and cities after President Goodluck Jonathan, a Christian from the south, was declared the victor of an April 16 election, defeating former military ruler and northern Muslim Muhammadu Buhari.
Observers and many Nigerians say the vote was the most credible in Africa's most populous nation for decades and world leaders have congratulated Jonathan. But Buhari says the count was rigged and his supporters have refused to accept defeat.
Nigeria's Civil Rights Congress (CRC) said more than 500 people were killed on Monday and Tuesday in three towns alone -- Zonkwa, Kafanchan and Zangon Kataf -- in the southern part of Kaduna state, one of the worst-hit areas.
"The victims were encircled, raided and hacked to death and their homes burned," CRC president Shehu Sani said in a report based on testimony from the group's members in the communities.
Churches, mosques, homes and shops were set ablaze in the rioting. Although a military-enforced curfew brought the violence under control in major cities after little more than a day, soldiers took longer to deploy to more remote towns.
Sani said the CRC -- which is based in Kaduna -- confirmed 316 dead in Zonkwa, 147 in Zangon Kataf and 83 in Kafanchan.
"Soldiers did not get there until afterwards," he said.
A tally of figures from Red Cross officials, health workers and Reuters witnesses who visited morgues showed the toll was at least 130. But that was only in a few major towns and cities, excluding those mentioned in the CRC report.
More than 40,000 people were displaced by the violence.
Nigeria is home to more than 250 ethnic groups, most of whom live peacefully side by side. The majority of the Muslim population live in the north while the south is predominantly Christian, although sizeable minorities live in both regions.
Jonathan and Buhari have condemned the unrest, but fiercely contested governorship elections are due in most of Nigeria's states on Tuesday and there are fears of further violence where there are close races between the ruling People's Democratic Party (PDP) and Buhari's Congress for Progressive Change (CPC).
The polls in Kaduna and Bauchi states in the north have been postponed by two days because of the security situation there.
"The CPC is being seen as a Muslim party and the PDP is being seen as a Christian party. Whichever way the election goes, there is going to be a problem," Sani said of Kaduna.
The CPC plans to go to court to challenge the presidential election result, on the grounds that the ruling party and electoral commission conspired to rig computers at collation centers and deprive him of victory.
"The facade at the polling units must be unmasked for this election to be seen for the sham that it truly was," Tunde Bakare, an evangelical pastor and Buhari's running mate in the presidential race, told reporters in Lagos on Saturday.
"No legitimate government can be formed on a stolen mandate." The results announced by the Independent National Electoral Commission (INEC) showed Jonathan had more than 22 million votes compared to around 12 million for Buhari.