Lagos, Nigeria - Several people were killed and dozens injured in weekend clashes between two communities in southwestern Nigeria which police said on Monday were linked to this week's controversial national census.
The census is the first attempt in 15 years to count residents in Africa's most populous country.
Headcounts have been controversial in Nigeria since independence from Britain in 1960 because population is the yardstick used to allocate oil revenues and decide political representation.
But as well as the logistical challenges of a vast, chaotic, impoverished country with few decent roads, organisers have to contend with competing regions, religious communities and ethnic groups all eager to assert their numerical superiority.
These issues are explosive in Nigeria, where at least 14,000 people have died in ethnic, religious or political violence since the return to civilian rule in 1999 after 15 years of military dictatorship.
The bloodiest contests for power usually occur between small villages fighting over disputed boundaries or political control of local councils.
Organisers have excluded ethnicity and religion from the census questionnaire to avoid rigging and fighting by rival interest groups that discredited previous headcounts.
However, some communities are hoping to use the census to record their claims to land or property, and that is what appeared to be happening in the village of Taribo in southwestern Ondo state over the weekend, police said.
They said fighting broke out between the Ikale and Ijaw communities over ownership of Taribo. Police did not have a toll, but several newspapers reported six people had died in the violence.
"Some people were feared dead in the clashes. The problem is related to the census. ... We are still investigating," a police spokesman said by phone from the Ondo state capital Akure.
The national census is scheduled for Tuesday to Saturday and the build-up has been marred by other incidents.
In northern Kano state, census takers torched the house and car of a census official over what they said was delayed payment of their fees, media reported.
In southern Rivers state, a similar protest ended with several census counters being arrested.
Elsewhere, arguments have broken out over alleged attempts by local authorities to place their loyalists as count takers instead of letting officials named by the National Population Commission do the job.
Estimates put Nigeria's population somewhere between 120 million and 150 million, and the government says it needs better data to do its job. The European Union and other foreign donors have paid more than half of the $266 million budget for the count.
Head counts in 1963 and 1973 were annulled after wrangling over the figures by Nigeria's three main ethnic groups inflamed political and religious tensions.